FORCES ACTING ON GRAVITY DAM
The Bureau of Indian Standards code IS 6512-1984 “Criteria for design of solid gravity dams” recommends that a gravity dam should be designed for the most adverse load condition of the seven given type using the safety factors prescribed.
1. Load combination A (construction condition): Dam completed but no water in reservoir or tail water
2. Load combination B (normal operating conditions): Full reservoir elevation, normal dry weather tail water, normal uplift, ice and silt (if applicable)
3. Load combination C: (Flood discharge condition) - Reservoir at maximum flood pool elevation ,all gates open, tail water at flood elevation, normal uplift, and silt (if applicable)
4. Load combination D: Combination of A and earthquake
5. Load combination E: Combination B, with earthquake but no ice
6. Load combination F: Combination C, but with extreme uplift, assuming the drainage holes to be Inoperative
7. Load combination G: Combination E but with extreme uplift (drains inoperative)
Water Pressure (P) is the major external force exerted by the water stored in the Reservoir on the upstream face of the dam. It can be calculated by the law of hydrostatic pressure distribution; which is triangular in shape as shown in Fig. 3.3.
(a) When u/s face is vertical :
When the upstream face is vertical, the intensity of pressure is zero at the water surface and equal to γw • H at the base.
Earth quake pressure, Horizontal Component(PH) , (ii) Vertical Component(PV) = Weight of water in ABCD portion ,
2. Weight of the Dam :
The weight of the dam per unit length is given by the product of the area of crosssection of the dam and the specific weight of the Construction material, i.e. concrete, and masonary it acts vertically downwards at the centre of gravity of the section.
dam may be divided into smaller sections of simple geometrical shapes such as triangles,rectangles, etc.
weight of each of these acting at its centre of gravity may be considered.
Weight of any part of dam = cross-sectional area of that part x specific weight of material
3. Uplift Pressure :
Uplift pressure is defined as the force exerted by water penetrating through the pores, cracks, fissures within the body of the dam, at the contact between the dam and its
foundation, and within the foundation.
acts vertically upwards
it causes a reduction in the effective weight
Ice Pressure :
Ice pressure is exerted on a dam by a sheet of ice formed on the entire water surface of the reservoir, when it is subjected to expansion and contraction with changes in temperature.
The coefficient of thermal expansion of ice being five times more than that of concrete, the dam face has to resist the force due to expansion of ice. This force acts linearly along the length of the dam, at the reservoir level.
As per IS : 6512 - 1984, ice pressure may be taken equal to 250 kN/m2 applied to the face of the dam over the anticipated area of contact of i
FORCES ACTING ON GRAVITY DAM
5. Wave Pressure :
Wind blowing over the water surface in the reservoir exerts a drag on the surface due to which ripples and waves are formed. The impact of these waves Produces a pressure on the upper portion of the dam. The magnitude of the wave pressure mainly depends on the dimensions of the waves which in turn depend on the extent of water surface and the wind velocity.
Silt pressure
The weight and the pressure of the submerged silt are to be considered in addition to weight and pressure of water. The weight of the silt acts vertically on the slope and pressure horizontally, in a similar fashion to the corresponding forces due to water. It is recommended that the submerged density of silt for calculating horizontal pressure may be taken as 1360 kg/m³. Equivalently, for calculating vertical force, the same may be taken as 1925 kg/m³.
Wind Pressure :
Wind pressure is required to be consider only on that portion of the dam structure which is exposed to the action of wind.
Normally wind pressure is taken as 1 to 1.5 kN/m2 for the area exposed to the wind pressure.
Wind pressure is not a significant force and therefore, sometimes, not considered in design of a dam.
Earthquake Forces (Seismic Forces) :
Earthquake or seismic activity is associated with complex oscillating patterns of acceleration and ground motions, which generate transient dynamic loads due to inertia of the dam and the retained body of water.
Horizontal and vertical accelerations are not equal, the former being of greater intensity.
The earthquake acceleration is usually designated as a fraction of the acceleration due to gravity and is expressed as α⋅g, where α is the Seismic Coefficient. The seismic coefficient depends on various factors, like the intensity of the earthquake, the part or zone of the country in which the structure is located, the elasticity of the material of the dam and its foundation, etc.
For the purpose of determining the value of the seismic coefficient which has to be adopted in the design of a dam, India has been divided into five seismic zones, depending upon the severity of the earthquakes which may occur in different places. A map showing these zones is given in the Bureau of Indian Standards code IS: 1893-2002 (Part-1) “Criteria for earthquake resistant design of Structures (fourth revision)”, and has been reproduced in Figure 28.
According to IS : 1893 - 2002, the design value of horizontal seismic coefficient
(Ah) may be determined by one of the two methods
(a) Seismic coefficient method
The total design lateral force or design seismic base shear (VB) along any principal direction shall be determined by the following expression.
Hydrodynamic Pressure :
Horizontal acceleration acting towards the reservoir causes a momentary increase ln the water pressure as the foundation and dam accelerate towards the reservoir and the water resists movement owing to its inertia.
The extra pressure ex
FORCES ACTING ON GRAVITY DAM
5. Wave Pressure :
Wind blowing over the water surface in the reservoir exerts a drag on the surface due to which ripples and waves are formed. The impact of these waves Produces a pressure on the upper portion of the dam. The magnitude of the wave pressure mainly depends on the dimensions of the waves which in turn depend on the extent of water surface and the wind velocity.
Silt pressure
The weight and the pressure of the submerged silt are to be considered in addition to weight and pressure of water. The weight of the silt acts vertically on the slope and pressure horizontally, in a similar fashion to the corresponding forces due to water. It is recommended that the submerged density of silt for calculating horizontal pressure may be taken as 1360 kg/m³. Equivalently, for calculating vertical force, the same may be taken as 1925 kg/m³.
Wind Pressure :
Wind pressure is required to be consider only on that portion of the dam structure which is exposed to the action of wind.
Normally wind pressure is taken as 1 to 1.5 kN/m2 for the area exposed to the wind pressure.
Wind pressure is not a significant force and therefore, sometimes, not considered in design of a dam.
Earthquake Forces (Seismic Forces) :
Earthquake or seismic activity is associated with complex oscillating patterns of acceleration and ground motions, which generate transient dynamic loads due to inertia of the dam and the retained body of water.
Horizontal and vertical accelerations are not equal, the former being of greater intensity.
The earthquake acceleration is usually designated as a fraction of the acceleration due to gravity and is expressed as α⋅g, where α is the Seismic Coefficient. The seismic coefficient depends on various factors, like the intensity of the earthquake, the part or zone of the country in which the structure is located, the elasticity of the material of the dam and its foundation, etc.
For the purpose of determining the value of the seismic coefficient which has to be adopted in the design of a dam, India has been divided into five seismic zones, depending upon the severity of the earthquakes which may occur in different places. A map showing these zones is given in the Bureau of Indian Standards code IS: 1893-2002 (Part-1) “Criteria for earthquake resistant design of Structures (fourth revision)”, and has been reproduced in Figure 28.
According to IS : 1893 - 2002, the design value of horizontal seismic coefficient
(Ah) may be determined by one of the two methods
(a) Seismic coefficient method
The total design lateral force or design seismic base shear (VB) along any principal direction shall be determined by the following expression.
Hydrodynamic Pressure :
Horizontal acceleration acting towards the reservoir causes a momentary increase ln the water pressure as the foundation and dam accelerate towards the reservoir and the water resists movement owing to its inertia.
The extra pressure ex
Topics:
1. Causes of Failures of Weirs on Permeable Foundations
2. Bligh’s Creep Theory
3. Lane’s Weighted Creep Theory
4. Khosla’s Theory
5. Application of Correction Factors
6. Launching Apron
Topics:
1. Types of Gravity Dam
2. Forces Acting on a Gravity Dam
3. Causes of failure of Gravity Dam
4. Elementary Profile of Gravity Dam
5. Practical Profile of Gravity Dam
6. Limiting height of Gravity Dam
7. Drainage and Inspection Galleries
Concrete Gravity Dam Components
A gallery is a small passage in a dam for providing an access to the interior of the dam.
The gallery is usually rectangular in shape with its top and bottom either flat or semi circular.
For a gallery with its top and bottom flat, it is necessary that all the corners should be rounded. The width of gallery generally varies from 1.5 to 1.8 m. The height of the gallery in between 2.2 to 2.4 m, so that a person can easily walk inside it.
To provide drainage of the dam section.
2. To provide space for equipment required for drilling holes and grouting the hole to form a grout curtain in the foundation.
3. To provide space for header and return pipes for post cooling of concrete.
4. A gallery provide an access to the interior of the dam for inspection ard maintenance.
5. A Gallery also provides space for installing various instruments in the dam to study its structural behaviour.
6. A gallery can provide space for the mechanical and electrical equipment required for the operation of gates for spillways and outlets.
A shaft is a vertical opening provided in a dam. Shafts are required for locating headers of the post cooling system and for locating measuring devices.
Shafts are also required for the movement of elevators and the hoisting equipment. Sometimes shafts are constructed inclined to connect two galleries or the same gallery at two different elevations by a staircase or a lift arrangement.
A plumb line shaft is constructed at the maximum section of the dam to make observations of the deflection of the dam under loads.
A plumb bob is suspended by a wire fixed at the top of the shaft. As the dam deflects relative to the base, the plumb bob also moves by the same amount.
A stilling well shaft is a special shaft used to record fluctuations of the water level in the reservoir. The shaft is connected to the reservoir at a point below the minimum reservoir level.
There is a floating mechanism in the stilling well shaft which records fluctuations in the water level.
The spillway in a gravity dam is called overflow section. Spillway is provided to dispose of surplus water from the reservoir to the downstream.
Spillways are provided for all dams as a safety measure against overtopping and the consequent damages, and failure. spillway may be located either in the middle of the dam or at the end of the dam near abutment.
It must have adequate discharge capacity.
It must be hydraulically and structurally safe.
The surface of the spillway must be erosion resistant.
It should be provided with some device for the dissipation of excess energy
The portion of the gravity dam other than the spillway is a non-overflow section, a road is located on the non-overflow section of the dam.
At the one end of a gravity dam a power house is located. Water from the reservoir passes tnrough penstock and rotates the turbine provided at power elevations to produce electricity.
Water flowing over a spillway has a ver
These slides will help you understand the concept of Specific Energy Curves including Critical depth, Critical velocity, Condition of minimum specific energy, and Condition for maximum discharge.
TERZAGHI’S BEARING CAPACITY THEORY
DERIVATION OF EQUATION TERZAGHI’S BEARING CAPACITY THEORY
TERZAGHI’S BEARING CAPACITY FACTORS
Download vedio link
https://youtu.be/imy61hU0_yo
Topics:
1. Causes of Failures of Weirs on Permeable Foundations
2. Bligh’s Creep Theory
3. Lane’s Weighted Creep Theory
4. Khosla’s Theory
5. Application of Correction Factors
6. Launching Apron
Topics:
1. Types of Gravity Dam
2. Forces Acting on a Gravity Dam
3. Causes of failure of Gravity Dam
4. Elementary Profile of Gravity Dam
5. Practical Profile of Gravity Dam
6. Limiting height of Gravity Dam
7. Drainage and Inspection Galleries
Concrete Gravity Dam Components
A gallery is a small passage in a dam for providing an access to the interior of the dam.
The gallery is usually rectangular in shape with its top and bottom either flat or semi circular.
For a gallery with its top and bottom flat, it is necessary that all the corners should be rounded. The width of gallery generally varies from 1.5 to 1.8 m. The height of the gallery in between 2.2 to 2.4 m, so that a person can easily walk inside it.
To provide drainage of the dam section.
2. To provide space for equipment required for drilling holes and grouting the hole to form a grout curtain in the foundation.
3. To provide space for header and return pipes for post cooling of concrete.
4. A gallery provide an access to the interior of the dam for inspection ard maintenance.
5. A Gallery also provides space for installing various instruments in the dam to study its structural behaviour.
6. A gallery can provide space for the mechanical and electrical equipment required for the operation of gates for spillways and outlets.
A shaft is a vertical opening provided in a dam. Shafts are required for locating headers of the post cooling system and for locating measuring devices.
Shafts are also required for the movement of elevators and the hoisting equipment. Sometimes shafts are constructed inclined to connect two galleries or the same gallery at two different elevations by a staircase or a lift arrangement.
A plumb line shaft is constructed at the maximum section of the dam to make observations of the deflection of the dam under loads.
A plumb bob is suspended by a wire fixed at the top of the shaft. As the dam deflects relative to the base, the plumb bob also moves by the same amount.
A stilling well shaft is a special shaft used to record fluctuations of the water level in the reservoir. The shaft is connected to the reservoir at a point below the minimum reservoir level.
There is a floating mechanism in the stilling well shaft which records fluctuations in the water level.
The spillway in a gravity dam is called overflow section. Spillway is provided to dispose of surplus water from the reservoir to the downstream.
Spillways are provided for all dams as a safety measure against overtopping and the consequent damages, and failure. spillway may be located either in the middle of the dam or at the end of the dam near abutment.
It must have adequate discharge capacity.
It must be hydraulically and structurally safe.
The surface of the spillway must be erosion resistant.
It should be provided with some device for the dissipation of excess energy
The portion of the gravity dam other than the spillway is a non-overflow section, a road is located on the non-overflow section of the dam.
At the one end of a gravity dam a power house is located. Water from the reservoir passes tnrough penstock and rotates the turbine provided at power elevations to produce electricity.
Water flowing over a spillway has a ver
These slides will help you understand the concept of Specific Energy Curves including Critical depth, Critical velocity, Condition of minimum specific energy, and Condition for maximum discharge.
TERZAGHI’S BEARING CAPACITY THEORY
DERIVATION OF EQUATION TERZAGHI’S BEARING CAPACITY THEORY
TERZAGHI’S BEARING CAPACITY FACTORS
Download vedio link
https://youtu.be/imy61hU0_yo
It contains detailed information about a Gravity Dam........it also conataims the information in brief & pictures giving a clear view of the Gravity Dams...........It also contains formulas with details of their terms.........
canal fall types,design steps of vertical drop fall, design of sheet pile, cistern, impervious floor, bligh creep theory, khosla theory, cutoff drop structure, wing walls
15 05-05 wind uplift - the next big lift - roof tech presentationJRS Engineering
All exterior building components need to be properly designed to withstand the forces of nature. However, many of the buildings being constructed today are not properly designed or the responsibility has been improperly designated to a contractor. This has resulted in many failures, both minor and major, of various building envelope components.
Wind Uplift: The Next Big Lift will focus on the aspects of designing roofing to properly withstand the forces of wind that act upon the building. We will go through the NBC design requirements and how they relate to the CSA A123.21 testing standard. We will discuss the pitfalls of using FM Global references in our specs and how it interacts with our codes. We will also discuss the shortfalls of our current building code and the direction of the next code edition.
Infinite and finite length of blanket
A natural impervious blanket of large areal extent if available may be considered as a balnket of infinite length
For a blanket of infinite length, the solution of equation (iv) is
In this case for the convenience, the point x = 0 is taken at the downstream end of the blanket and hence h0 is the total loss of head through the blanket upto the end of the blanket.
As a measure of the efficiency of a blanket of any length x (where x may be infinite or a finite length) a length Xr is considered which is known as equivalent resistance of the foundation and is defined below.
It may be defined as the length of a prism of the foundation soil of thickness Zf and coefficient of permeability kf which under the loss of head h would carry flow equivalent to the flow which passes the blanket system under the same loss of head. Thus
(2) Solution for finite length of blanket :
For a blanket of uniform thickness and finite length of blanket ihe solution equation (iv) is
which h is the loss of head through the blanket upto any point at a distance and hn is a constant for computing h. hn depends on the total head loss of the system of which the blanket is a part and on the ratio of the blanket to the remainder of system. *
From equation (viii) at x - 0, h = 0, and hence in this case the point x = 0 is taken at the upstream end of the blanket.
Differentiating both sides of equation (viii) with respect to x, we get
This study was competent studied earth dams and species and its history and the factors influencing them and the other part of a study of the most important risks that affect earth dams (seepage through earth dams) and how to calculate the leak and methods of their account and types the seepage and forms of cost and what are the ways process is treated with filters.
1. INTRODUCTION TO SEEPAGE THROGH EARTH DAM
2.METHODS CALCULATION SEEPAGE THROGH EARTH
DAM
3. ENTRANCE, DISCHARGE, AND TRANSFARE
CONDITIONSOF LINE OF SEEPAGE
4.SIMULATE THE PRESSURE ON THE EARTH DAM USING SAP 2000 PROGRAM
5.DESIGN FILTER TO CONTROLED THE SPAAGE IN EARTH DAM
PracticalProfileofSpillwaY
When the profile for the crest of the ogee spillway is plotted over the triangular profile the section of a gravity dam (non-overflow section) ,it is found that it goes beyond vie downstream face of the dam , thu requiring thickening of the section for the spillway .
However,this extra concrete can be saved by shifting the curve of the nappe in a backward direction until this curve becomes tangential to the downstream face of the dam .
Design of spillway
Design an ogee spillway for concrete gravity dam, for the following data :
(1) Average river bed level = 100.0 m
(2) R.L. of spillway crest =204.0 m
(3) Slope of d/s face of gravity dam = 0.7 H : 1 V
(4) Design discharge = 8000 cumecs
(5) Length of spillway = 6 spans with a clear width of 10 m each.
(6) Thickness of each pier = 2.5 m
If h/Hd is greater than 1.7 than high spillway so effect of velocity is neglected
The co-ordinates from x = 0 to x = 27.4 m are worked out in the table below :
Section of an Earth Dam :
The design of an earth dam essentially consists of determining such a cross section
the dam which when constructed with the available materials will fulfill its required
tion with adequate safety. Thus there are two aspects of the design of an earth dam.
b) Foundation pervious to a moderate depth, after which impervious strata is available :
(c) Foundation pervious to a great depth:
CASE 2 ONLY FINE GRAVEL OR COARSE SAND IS AVAILABLE
PROVIDE DIAPHRAM TYPE DAM WITH SUITABLE ARRANGEMENTS
CASE 3
ONLY SILT AND CLAY IS AVAILABLE
NO CORE
ONLY IMPERVIOUS BLANKED AND ROCK TOE PROVIDES
SEEPAGE ANALYSIS
ASSUMPTIONS
FLOW IS – TWO DIMENTIONAL
Soil is INCOMPRESSIBLE SOIL
Soil is homogeneous and isotropic
Soil is fully saturated
Flow is steady
Darcys law is valid
Phreatic line – (seepage line)
Line within the dam section having positive hydrostatic pressure at below section and negative hydrostatic pressure at above section
Line has atmospheric pressure itself
Separation line of saturated and non saturated portion
Casagrande method of determining seepage line
Water flowing over a spillway acquires a lot of kinetic energy because of the conversio of the potential energy into kinetic energy.
If the water flowing with such a high velocity is discharged into the river it will scour the river bed.
If the scour is not properly controlled it may extend backward and may endanger the spillway and the dam.
Types of Gravity Dam
Forces Acting on a Gravity Dam
Causes of failure of Gravity Dam
Elementary Profile of Gravity Dam
Practical Profile of Gravity Dam
Limiting height of Gravity Dam
Drainage and Inspection Galleries
Flood Loads are part of Environmental Loads which act on bridges that are constructed over streams. Bridges constructed over river crossings must be designed for flood loads.
Dalton’s law of evaporation
The rate of evaporation depends upon the difference between the saturation vapour pressure in the air above
E= C(es-ea)
where c – coefficient depends upon barometric pressure
Es – saturation vapour pressure
Ea - Vapour pressure above 2 m height of water
Factors affecting
Temperature
Wind velocity
Atmospheric pressure
Nature of evaporating surface
Depth of water supply
Impurities in water
Energy budget method
LOW OF CONSERVATION of energy
Energy required is estimated by incoming outgoing, and stored energy in a specific time period
Total energy received from suns radiation = energy reflected + change in energy + energy required for evaporation
Energy budget method
most accurate method (evaporation is a function of the energy state of the water system)
difficult to evaluate all terms
energy balance equation has to be simplified
empirical formulas are used (although radiation measurements are preferable)
Water budget method
Characteristics:
Simple
Difficult to estimate Qd and Qs
Unreliable, accuracy will increase as Δt increases
Measurement et -
Direct measurement –
1 . Tank & lysimeter method
2. Field experimental method- no runoff no percolation
3. Soil moisture studies – gw deep
4. Integration method – laege area
5. Inflow and outflow studies
Infiltration rate
Infiltration capacity : The maximum rate at which, soil at a given time can absorb water.
f = fc when i ≥ fc
f = f 0when i < fc
where fc = infiltration capacity (cm/hr)
i = intensity of rainfall (cm/hr)
f = rate of infiltration (cm/hr)
Horton’s Formula:
This equation assumes an infinite water supply at the surface i.e., it assumes saturation conditions at the soil surface.
For measuring the infiltration capacity the following expression are used:
f(t) = fc + (f0 – fc) e–kt for
where k = decay constant ~ T-1
fc = final equilibrium infiltration capacity
f0 = initial infiltration capacity when t = 0
f(t) = infiltration capacity at any time t from start of the rainfall
td = duration of rainfall
Double Ring Infiltrometer
Infiltration indices The average value of infiltration is called infiltration index.
Two types of infiltration indices
φ – index (PHI INDEX)
w –index
PHI INDEX
- defined as average rate of rainfall such that excess volume of rainfall represents direct runoff
- unit is cm/hr or……
W INDEX
- average rate of loss (infiltration) averaged over whole storm period
- w index = P- Q- S
T
THUS phi index has to be some what than w index
IS 4987 - 1968
IN PLAINS – 520 km2
Elevation upto 1000 m – 260 to 390 km2
Hilly area – 130 km2
It is recommended that 10% of raingauge must be self recording type
ENERGY DISSIPATORS
stilling basin
A stilling basin is defined as a structure in which a hydraulic jump used for energy dissipation is confined either partly or entirely.
Certain auxiliary devices such as chute blocks, sills, baffle walls, etc. are usually provided in the stilling basins to reduce the length of the jump and thus to reduce the length and the cost of the stilling basin.
Moreover, these devices also improve the dissipation action of the basin and stabilize the jump.
Chute Blocks :
These are triangular blocks with their top surface horizontal. These are installed at the toe of the spillway just at upstream end of the stilling basin.
They act as a serrated device at the entrance to the stilling basin. They furrow the incoming jet and lift a portion of it ab0ve the floor.
These blocks stabilise the jump and thus improve its performance, these also decrease the length of the hydraulic jump.
Basin Blocks or Baffle Blocks or Baffle Piers :
These are installed on the stilling basin floor between chute blocks and the end sill. These blocks also stabilise the formation of the jump.
Moreover, they increase the turbulence and assist in the dissipation of energy.
They help in breaking the flow and dissipate energy mostly by impact. These baffle blocks are sometimes called friction blocks.
Sills and Dentated Sills :
Sill or more preferably dentated sill is generally provided at the end of the stilling basin.
The dentated sill diffuses the residual portion of the high velocity jet reaching the end of the basin. They, therefore, help in dissipating residual energy and to reduce the length of the jump or the basin.
particular location of these blocks mainly depends upon the initial Froude number (F1) and the velocity of the incoming flow. The stilling basins are usually rectangular in plan. These are made up of concrete.
[A] U.S.B.R. Stilling basins :
[B] Indian Standards Basins :
1. Horizontal apron - Type-I
2. Horizontal apron - Type-II
3. Sloping apron - Type-Ill
4. Sloping apron - Type-IV
Type I basin (F1 between 2.5 to 4.5)
Provide chute blocks and end sill
Length of basin = 4.3 y2 to 6.0 y2
Width of chute block = y1
Spacing = 2.5 y1
Height of chute block = 2y1
Length of chutes = 2y1
U.S.B.R. Type-II basin for F1 greater than 4.5 and v1 less than 15 m/sec.:
U.S.B.R. Type-Ill basin for F, greater than 4.5 and V1 greater than 15 m/sec :
Chutes and dentated sills provided
Baffle is not provided because of –velocity is high and cavitation is possible.
[B] Indian Standards Basins :
1. Horizontal apron - Type-I
2. Horizontal apron - Type-II
3. Sloping apron - Type-Ill
4. Sloping apron - Type-IV
1. Horizontal apron - Type-I
2. Horizontal apron - Type-II
3. Sloping apron - Type-Ill
4. Sloping apron - Type-IV
1. Horizontal apron - Type-I
2. Horizontal apron - Type-II
3. Sloping apron - Type-Ill
4. Sloping apron - Type-IV
IS Type-Ill basin is usually provided with a sloping apron for the entire len
CHECK STABILITY OF DAM FOR GIVEN SECTION
TOP WIDTH 7.5 M
HEIGHT OF DAM – 75 M
HEIGHT OF W.L. – 72 M
BATTER IS STARTING AT 45 M
PROJECTION FROM U.S 4.5 M
D/S PORTION LENGTH – 43.75 M
D/S SLOPE STARTED AT 12.5 M FROM TOP
D/S SLOPE 0.7 (H):1(V)
DRAINAGE GALLERY @ 48.7
5 M FROM TOE OF DAM
F Ф = 1.2
FC = 2.4
μ=0.7
SHEAR STRENGTH OF CONCRETE = c = 1400 KN/M^2
ΣV =
Weight of dam
(W1+W2+W3)
+
Vertical forces of water
(P1+P2)
–
Uplift Forces
(U1 + U2 +U3)
–
Vertical Acceleration of E.Q.
Moment of Weight Of Dam
(w1 + w2 + w3)
+
Moment of Weight of water
(p1 + p2)
-
Moment of water pressure
(p)
-
Moment of Uplift Forces
(U)
-
Moment of Inertia force
(vertical acceleration moment + Hori Acce.)
-
Moment Hydrodynemic Pressure
STABILITY OF SLOPES SEEPAGE CONTROL MEASURES AND SLOPE PROTECTION
a finite slope AB, the stability of which is to be analyzed.
The method Consists of assuming a number of trial slip circles, and finding the factor of safety of each.
The circle corresponding to the minimum factor of safely is the critical slip circle.
Let AD be a trial slip circle, with r as the radius and O as the centre of rotation
Let W be the weight of the soil of the wedge ABDA of unit thickness, acting through the centroid G.
The driving moment MD will be equal to W x, where x, is the distance of line of action of W from the vertical line passing through the centre of rotation O.
if cu is the unit cohesion, and l is the length of the slip arc AD, the shear resistance developed along the slip surface will be equal to cu • l, which act at a radial distance r from centre of rotation O.
When slip is imminent in a cohesive soil, a tension crack will always DevelOP by the top surface of the slope along which no shear resistance can develop,
The depth of tension crack is given by
The effect of tension crack is to shorten the arc length along which shear resistance gets mobilised to AB' and to reduce the angle δ to δ'.
The length of the slip arc to be taken in the computation of resisting force is only AB', since tension crack break the continuity at B'.
The weight of the sliding wedge is weight of the area bounded by the ground surface, slip circle arc AB' and the tension crack.
Hydraulic failures .... 40%
Seepage failures…….. 30%
Structural failures .... 30%
(1) Overtopping
(2) Erosion of u/s slope by waves
(3) Erosion of d/s slope by wind and rain
(4) Erosion of d/s toe
(5) Frost action
(1) Overtopping = the design flood is under estimated.
spillway capacity is not adequet
spillway gates are not properly operated
free board is not sufficient
excessive settlement of the foundation and dam
(2) Erosion of u/s slope by waves = The waves developed near the top water surface due to the winds, try to notch out the soil from the upstream face and may even, sometimes, cause the slip of the upstream slope.
Upstream stone pitching or riprap should, therefore, be provided to avoid such failures.
(3) Erosion of d/s slope by wind and rain = The rainwater flowing down the slope; may result in the formation of 'gullies' on the downstream slope thus damaging the dam which may generally lead to partial failure of the dam or in some cases it may cause complete failure of the dam.
Erosion of d/s toe : = Toe erosion may occur due to two reasons :
erosion due to tail water
erosion due to cross currents that may come from spillway buckets.
Frost action : = If the earth dam is located at a place where the temperature falls below the freezing point, frost may form in the pores of the soil in the earth dam.
When there is heaving, the cracks may form in the soil. This may lead to dangerous seepage and consequent failure.
Seepage failures : = Seepage failures may occur due to the following causes :
(1) Piping through the foundation
(2) Piping through the dam
(3) Sloughing of d/s toe
Structural failures :=
Structural failures in earth dams are generally shear failures leading to sliding of the tents or the foundations.
(1) u/s and d/s slope failures due to construction pore pressures
(2) u/s slope failure due to sudden drawdown
(3) D/s slope failure due to steady seepage
(4) Foundation slide due to spontaneous liquefaction
(5) Failure due to earthquake
(6) Failure by spreading
(7) Slope protection failures
(8) Failure due to damage caused by borrowing animals
(9) Failure due to holes caused by leaching of water soluable salts
Criteria for safe Design of Earth Dam :
Section of an Earth Dam :
The design of an earth dam essentially consists of determining such a cross section
the dam which when constructed with the available materials will fulfill its required
tion with adequate safety. Thus there are two aspects of the design of an earth dam.
The main components of an earth dam are as follows :
1. Impervious core
2. Pervious shell
3. Filter
4. Rock toe
5. U/S slope protection
6. D/S slope protection
7. Cutoff
core should not be less than 3 m and its height should be 1 m more than the maximum water level in the reservoir.
The upstream pervious zone provides free drainage during sudden drawdown. ,
Usually following types of filters are provided :
(1) Toe filter
(2) Horizontal drainage filter (blanket)
(3) Chimney drains
Such a filter is sometimes known as inverted filter or reverse filter.
Rock toe keeps the phreatic line well within the section and also facilitates drainage.
The following measures are taken to protect the slope.
(1) Rock riprap
(2) Concrete pavement
(3) Steel facing
(4) Bituminous pavement
(5) Precast concrete blocks
Cut off is required to
(1) reduce loss of stored water through foundation and abutments
(2) Prevent sub surface erosion by piping.
Cutoff may be provided in the following ways :
• by providing concrete cutoff wall
• by providing cutoff trench filled with impervious material
• by driving sheet pile
• by curtain grouting
irrigation water management deals with various management aspects such as canal management, designing irrigation systems, irrigation efficiency, scheduling and water quaility etc.
Immunizing Image Classifiers Against Localized Adversary Attacksgerogepatton
This paper addresses the vulnerability of deep learning models, particularly convolutional neural networks
(CNN)s, to adversarial attacks and presents a proactive training technique designed to counter them. We
introduce a novel volumization algorithm, which transforms 2D images into 3D volumetric representations.
When combined with 3D convolution and deep curriculum learning optimization (CLO), itsignificantly improves
the immunity of models against localized universal attacks by up to 40%. We evaluate our proposed approach
using contemporary CNN architectures and the modified Canadian Institute for Advanced Research (CIFAR-10
and CIFAR-100) and ImageNet Large Scale Visual Recognition Challenge (ILSVRC12) datasets, showcasing
accuracy improvements over previous techniques. The results indicate that the combination of the volumetric
input and curriculum learning holds significant promise for mitigating adversarial attacks without necessitating
adversary training.
About
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Technical Specifications
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
Key Features
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface
• Compatible with MAFI CCR system
• Copatiable with IDM8000 CCR
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
Application
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
6th International Conference on Machine Learning & Applications (CMLA 2024)ClaraZara1
6th International Conference on Machine Learning & Applications (CMLA 2024) will provide an excellent international forum for sharing knowledge and results in theory, methodology and applications of on Machine Learning & Applications.
Cosmetic shop management system project report.pdfKamal Acharya
Buying new cosmetic products is difficult. It can even be scary for those who have sensitive skin and are prone to skin trouble. The information needed to alleviate this problem is on the back of each product, but it's thought to interpret those ingredient lists unless you have a background in chemistry.
Instead of buying and hoping for the best, we can use data science to help us predict which products may be good fits for us. It includes various function programs to do the above mentioned tasks.
Data file handling has been effectively used in the program.
The automated cosmetic shop management system should deal with the automation of general workflow and administration process of the shop. The main processes of the system focus on customer's request where the system is able to search the most appropriate products and deliver it to the customers. It should help the employees to quickly identify the list of cosmetic product that have reached the minimum quantity and also keep a track of expired date for each cosmetic product. It should help the employees to find the rack number in which the product is placed.It is also Faster and more efficient way.
Saudi Arabia stands as a titan in the global energy landscape, renowned for its abundant oil and gas resources. It's the largest exporter of petroleum and holds some of the world's most significant reserves. Let's delve into the top 10 oil and gas projects shaping Saudi Arabia's energy future in 2024.
HEAP SORT ILLUSTRATED WITH HEAPIFY, BUILD HEAP FOR DYNAMIC ARRAYS.
Heap sort is a comparison-based sorting technique based on Binary Heap data structure. It is similar to the selection sort where we first find the minimum element and place the minimum element at the beginning. Repeat the same process for the remaining elements.
Hierarchical Digital Twin of a Naval Power SystemKerry Sado
A hierarchical digital twin of a Naval DC power system has been developed and experimentally verified. Similar to other state-of-the-art digital twins, this technology creates a digital replica of the physical system executed in real-time or faster, which can modify hardware controls. However, its advantage stems from distributing computational efforts by utilizing a hierarchical structure composed of lower-level digital twin blocks and a higher-level system digital twin. Each digital twin block is associated with a physical subsystem of the hardware and communicates with a singular system digital twin, which creates a system-level response. By extracting information from each level of the hierarchy, power system controls of the hardware were reconfigured autonomously. This hierarchical digital twin development offers several advantages over other digital twins, particularly in the field of naval power systems. The hierarchical structure allows for greater computational efficiency and scalability while the ability to autonomously reconfigure hardware controls offers increased flexibility and responsiveness. The hierarchical decomposition and models utilized were well aligned with the physical twin, as indicated by the maximum deviations between the developed digital twin hierarchy and the hardware.
4. Forces Acting on a Gravity
Dam : (May 2012, October
2012
forces acting on a gravity dam are as
follows :
Water Pressure
Weight of the Dam
Uplift Pressure
Ice Pressure
Wave Pressure
Silt Pressure
Wind Pressure
Earth quake pressure
30/1/2014 4
PREPARED BY V.H.KHOKHANI,
ASSISTANT PROFESSOR, DIET.
5. The forces to the dam include
AS per IS 6512:
30/1/2014 5
PREPARED BY V.H.KHOKHANI,
ASSISTANT PROFESSOR, DIET.
Stabilize
forces
1. Weight of
the dam
2. Thrust of
the tail
water
Destabilizing force
1. water pressure
2. Uplift
3. Forces due to waves
4. Ice pressure
5. Temperature stresses
6. Silt pressure
7. Seismic forces
8. Wind pressure
7. The Bureau of Indian
Standards code IS 6512-1984
“Criteria for design of solid
gravity dams” recommends
that a gravity dam should be
designed for the most adverse
load condition of the seven
given type using the safety
factors prescribed.
30/1/2014
PREPARED BY V.H.KHOKHANI,
ASSISTANT PROFESSOR, DIET.
7
8. 1. Load combination A (construction
condition): Dam completed but no water
in reservoir or tail water
2. Load combination B (normal
operating conditions): Full reservoir
elevation, normal dry weather tail
water, normal uplift, ice and silt (if
applicable)
3. Load combination C: (Flood
discharge condition) - Reservoir at
maximum flood pool elevation ,all gates
open, tail water at flood elevation,
normal uplift, and silt (if applicable)30/1/2014
PREPARED BY V.H.KHOKHANI,
ASSISTANT PROFESSOR, DIET.
8
9. 4. Load combination D:
Combination of A and earthquake
5. Load combination E:
Combination B, with earthquake
but no ice
6. Load combination F:
Combination C, but with extreme
uplift, assuming the drainage holes
to be Inoperative
7. Load combination G:
Combination E but with extreme
uplift (drains inoperative)30/1/2014
PREPARED BY V.H.KHOKHANI,
ASSISTANT PROFESSOR, DIET.
9
10. Water Pressure :
Water Pressure (P) is the major external
force exerted by the water stored in the
Reservoir on the upstream face of the dam.
It can be calculated by the law of
hydrostatic pressure distribution; which is
triangular in shape as shown in Fig. 3.3.
(a) When u/s face is vertical :
When the upstream face is vertical, the
intensity of pressure is zero at the water
surface and equal to γw • H at the base.
30/1/2014
PREPARED BY V.H.KHOKHANI,
ASSISTANT PROFESSOR, DIET.
10
12. When the u/s face is partly
vertical and partly inclined :
Forces can be resolved into two
components.
30/1/2014
PREPARED BY V.H.KHOKHANI,
ASSISTANT PROFESSOR, DIET.
12
(i) Horizontal
Component(P
H) = γw • H2 /2
(ii) Vertical
Component(PV)
= Weight of
water in ABCD
portion
14. Tail Water Pressure :
If there is tail water of height H' it
will have
30/1/2014
PREPARED BY V.H.KHOKHANI,
ASSISTANT PROFESSOR, DIET.
14
(i) Horizontal
Component(P
H) = γw • H’2 /2
(ii) Vertical
Component(PV)
= Weight of
water in EFG
portion
16. 2. Weight of the Dam :
The weight of the dam per unit
length is given by the product of the
area of crosssection of the dam and
the specific weight of the
Construction material, i.e. concrete,
and masonary it acts vertically
downwards at the centre of gravity
of the section.
30/1/2014
PREPARED BY V.H.KHOKHANI,
ASSISTANT PROFESSOR, DIET.
16
17. dam may be divided into smaller
sections of simple geometrical
shapes such as triangles,rectangles,
etc.
weight of each of these acting at its
centre of gravity may be
considered.
Weight of any part of dam = cross-
sectional area of that part x specific
weight of material
30/1/2014
PREPARED BY V.H.KHOKHANI,
ASSISTANT PROFESSOR, DIET.
17
19. 3. Uplift Pressure :
Uplift pressure is defined as the
force exerted by water penetrating
through the pores, cracks, fissures
within the body of the dam, at the
contact between the dam and its
foundation, and within the
foundation.
30/1/2014
PREPARED BY V.H.KHOKHANI,
ASSISTANT PROFESSOR, DIET.
19
20. acts vertically upwards
it causes a reduction in the
effective weight
30/1/2014
PREPARED BY V.H.KHOKHANI,
ASSISTANT PROFESSOR, DIET.
20
24. Ice Pressure :
Ice pressure is exerted on a dam by a sheet of ice
formed on the entire water surface of the
reservoir, when it is subjected to expansion and
contraction with changes in temperature.
The coefficient of thermal expansion of ice being
five times more than that of concrete, the dam
face has to resist the force due to expansion of ice.
This force acts linearly along the length of the
dam, at the reservoir level.
As per IS : 6512 - 1984, ice pressure may be
taken equal to 250 kN/m2 applied to the face of
the dam over the anticipated area of contact of ice
with the face of the dam.
30/1/2014
PREPARED BY V.H.KHOKHANI,
ASSISTANT PROFESSOR, DIET.
24
