1. Grouting, rock bolting, shotcrete/guniting, and cable anchorage are effective methods for improving rock mass properties.
2. Grouting involves injecting a liquid into cracks and fissures in rock to fill voids and strengthen the rock mass. Common grout materials include cement and chemical grouts.
3. Rock bolting reinforces unstable rock by drilling holes and anchoring steel bolts to take load off weak planes and increase shear resistance.
This document discusses India's lignite sector, including reserves, production, consumption, and power plants. It notes that India has estimated lignite reserves of 43 billion tonnes, with the largest reserves located in Tamil Nadu. Lignite production has increased at a 5.97% annual rate over the last decade. Approximately 75-80% of lignite produced is used for power generation. India has over 5,000 MW of installed lignite-based power generation capacity located primarily in Tamil Nadu, Gujarat, and Rajasthan. Key issues facing India's lignite mining include its geographic confinement, economic viability challenges due to low energy content and high moisture, and reliance on open-cast mining methods.
Hi everyone thanks for you to see our report again, and our report contains every single information about deep foundation just like advantages and disadvantages and types and here again just like the shallow foundation report we compared both with each other.
And from this link you read about shallow foundation
https://www.slideshare.net/mobile/AliRizgar/shallow-foundation-full-information
And from this email you can ask any thing to us
Alirizgar234@gmail.com
Mineralogy, Mode of occurrence, Distribution of India , Origin and use in ec...Thomas Chinnappan
This document summarizes barite and gypsum - two industrial minerals. It discusses their mineralogy, mode of occurrence, distribution in India, and uses. Barite often occurs as concretions in sedimentary rocks like limestone and is a major ore of barium. In India, it is highly abundant in Andhra Pradesh. Its main uses are as a weighting agent in drilling mud for oil exploration and in various industrial applications. Gypsum is an evaporite mineral found in sedimentary deposits associated with halite and other minerals. It is widely used in construction and agriculture due to its ability to absorb moisture and provide calcium to soils. India's main gypsum deposits are located in Rajasthan.
This document discusses the formation, properties, types, distribution, and uses of mica. It notes that India dominates the global mica market, exporting mainly to the US, Japan, Germany and other countries. The key points are:
- Mica forms from magmatic solutions in pegmatites and has a sheet structure composed of silicon and aluminum tetrahedra.
- The main types are muscovite, phlogopite, biotite and lepidolite. India's largest deposits are in Andhra Pradesh, Rajasthan, Jharkhand and Odisha.
- Mica has a range of industrial and commercial uses including insulation, pigments, and cosmet
1. Grouting, rock bolting, shotcrete/guniting, and cable anchorage are effective methods for improving rock mass properties.
2. Grouting involves injecting a liquid into cracks and fissures in rock to fill voids and strengthen the rock mass. Common grout materials include cement and chemical grouts.
3. Rock bolting reinforces unstable rock by drilling holes and anchoring steel bolts to take load off weak planes and increase shear resistance.
This document discusses India's lignite sector, including reserves, production, consumption, and power plants. It notes that India has estimated lignite reserves of 43 billion tonnes, with the largest reserves located in Tamil Nadu. Lignite production has increased at a 5.97% annual rate over the last decade. Approximately 75-80% of lignite produced is used for power generation. India has over 5,000 MW of installed lignite-based power generation capacity located primarily in Tamil Nadu, Gujarat, and Rajasthan. Key issues facing India's lignite mining include its geographic confinement, economic viability challenges due to low energy content and high moisture, and reliance on open-cast mining methods.
Hi everyone thanks for you to see our report again, and our report contains every single information about deep foundation just like advantages and disadvantages and types and here again just like the shallow foundation report we compared both with each other.
And from this link you read about shallow foundation
https://www.slideshare.net/mobile/AliRizgar/shallow-foundation-full-information
And from this email you can ask any thing to us
Alirizgar234@gmail.com
Mineralogy, Mode of occurrence, Distribution of India , Origin and use in ec...Thomas Chinnappan
This document summarizes barite and gypsum - two industrial minerals. It discusses their mineralogy, mode of occurrence, distribution in India, and uses. Barite often occurs as concretions in sedimentary rocks like limestone and is a major ore of barium. In India, it is highly abundant in Andhra Pradesh. Its main uses are as a weighting agent in drilling mud for oil exploration and in various industrial applications. Gypsum is an evaporite mineral found in sedimentary deposits associated with halite and other minerals. It is widely used in construction and agriculture due to its ability to absorb moisture and provide calcium to soils. India's main gypsum deposits are located in Rajasthan.
This document discusses the formation, properties, types, distribution, and uses of mica. It notes that India dominates the global mica market, exporting mainly to the US, Japan, Germany and other countries. The key points are:
- Mica forms from magmatic solutions in pegmatites and has a sheet structure composed of silicon and aluminum tetrahedra.
- The main types are muscovite, phlogopite, biotite and lepidolite. India's largest deposits are in Andhra Pradesh, Rajasthan, Jharkhand and Odisha.
- Mica has a range of industrial and commercial uses including insulation, pigments, and cosmet
Effect of underground tunnelling by (TBM) on foundations of existing structuresKishor Ade
This document discusses a dissertation on the effect of underground tunnelling by tunnel boring machine (TBM) on existing structures' foundations. It introduces the topic, provides a literature review on previous related studies, and outlines the methodology, which involves finite element modeling and analysis of shallow and raft foundations at different tunnel depths using Midas GTS NX software. The results found that tunnelling was suitable for raft and shallow foundations on hard and soft murrum soils when the tunnel crown depth was 20-25m below foundations, as displacements did not exceed code limits. Tunnelling was not suitable under shadu soil foundations.
This document provides an overview of stromatolites and microbial mat structures. It begins with definitions of stromatolites from early literature and discusses how understanding of these structures has evolved over time. It describes different classifications of stromatolites proposed by various researchers based on their morphology. The document also discusses microbial mat structures and reviews the distribution of stromatolites through geological time. It provides context on studies of Indian stromatolites, including those in the Vindhyan Basin, which are the focus of the project. The aim and objectives of the project to investigate the diversity and abundance of stromatolites and microbial mat structures in the Vindhyan Basin are also outlined.
metamorphic rocks and their distinguishing features-megascopic and microscopic study of gneiss, schist, quartzite, marble and slate
Properties and characteristics and uses of metamorphic rocks
Geology is the study of the Earth, including its origin, structure, composition and processes that have shaped it over time. It involves studying the Earth through observation, analysis and synthesis at locations like libraries, laboratories, museums and field sites. Geology is related to other sciences and has many branches of study. It is important to study geology because geological processes and resources influence human civilization, environments and hazards, and geology underpins engineering and understanding of landforms and Earth's history.
The document summarizes different techniques for retaining deep excavations, including contiguous piles, secant piles, sheet piling, diaphragm walls, soldier piles with lagging, and presents case studies of their use. It discusses techniques such as contiguous piles with soil anchors used for the IT Tower Lahore project requiring excavation to a depth of 65 feet, and contiguous piling with 9 layers of anchors for the Alamgir Tower Lahore project requiring excavation to 85 feet. It also summarizes the use of slurry walls for the large Washington Convention Center project requiring excavation up to 55 feet deep.
El documento describe los diferentes tipos de formaciones hidrogeológicas y sus características, incluyendo acuíferos, acuitardos y acuífugos. Explica que Honduras tiene varios tipos de acuíferos según su ubicación geográfica y composición geológica. Finalmente, concluye la importancia de entender las formaciones hidrogeológicas para evaluar el potencial y vulnerabilidad de los recursos hídricos subterráneos.
Este documento describe la ingeniería geotécnica y sus principales aspectos. La ingeniería geotécnica estudia las propiedades de los suelos y rocas para diseñar cimientos y estructuras. Un ingeniero geotécnico investiga las propiedades de los materiales en el sitio, evalúa riesgos como deslizamientos, y diseña cimientos y fundaciones apropiadas. Algunos logros notables de la ingeniería geotécnica incluyen el Taj Mahal, el túnel Seikan y el aeropuerto Chek Lap
Shallow foundations transfer structural loads to soil near the surface and are suitable when soil has good bearing capacity. They include spread, combined, and mat/raft foundations. Spread footings are most common, supporting individual columns or walls. Combined and mat foundations are used when loads overlap or are very high. Shallow foundations are simpler and cheaper than deep foundations but have limitations regarding soil conditions and structural loads.
Diagenesis is the process by which changes occur in sediment after it is deposited until the onset of metamorphism. During diagenesis, loose sediments are transformed into a solid rock through compaction, recrystallization, dissolution, replacement, cementation, and other processes. These diagenetic processes are important as they can significantly modify the composition and properties of the original sediment and even destroy sedimentary structures in rare cases.
FLUID INCLUSION WALL ROCK ALTERATION in economic geologyThomas Chinnappan
This document discusses fluid inclusions and wall rock alteration related to hydrothermal fluids. It defines fluid inclusions as tiny samples of trapped fluid in minerals, and describes hydrothermal fluids as underground hot water rich fluids capable of transporting metals. Wall rock alteration is defined as the reaction of hydrothermal fluids with enclosing rocks, causing mineralogical changes. The document outlines different types of wall rock alteration including potassic, phyllite, carbonatization, tourmalinization, greisenization, and silication alteration. It concludes that alteration phenomena are effectively studied in igneous rocks where progressive clay mineral alteration may occur.
Phd Thesis: Numerical modelling of surface subsidence associated with block c...Dr. Alex Vyazmensky
Through the use of an integrated FEM/DEM-DFN modelling technique this thesis presents a new approach to simulation of block caving induced surface subsidence allowing physically realistic simulation of subsidence development from caving initiation to final subsidence deformation. As part of the current research, a fundamental issue in modelling, the selection of representative equivalent continuum rock mass modelling parameters, is investigated and a procedure for calibration of modelling parameters devised. Utilizing a series of conceptual numerical experiments our fundamental understanding of the mechanisms and the role of the factors controlling block caving subsidence development is investigated. Valuable insights gained from this work are summarized in a preliminary subsidence classification and an influence assessment matrix of the governing factors. These are intended as an aid to engineering judgment for decision makers at the pre-feasibility and mine design stages.
This study also addresses one of the most challenging problems in mining rock engineering - the interaction between block cave mining and a large overlying open pit, focusing on caving induced step-path failure initialization. Using a novel approach to modelling data analysis a clear link between caving propagation, step-path failure development within the slope, and the resultant surface subsidence is established. In addition, FEM/DEM-DFN modelling is applied to the preliminary analysis of the block caving triggered slope failure at Palabora open pit.
This research represents a valuable contribution to block caving geomechanics and is a major step forward in the understanding of complex block caving subsidence phenomena, paving the way to more reliable assessment of caving induced subsidence deformations.
Tunnel and Underground Excavation PresentationChandan Pradhan
This document discusses tunnels and underground excavations. It defines different types of underground structures like tunnels, shafts, adits, and inclines. Tunnels are classified based on their size, shape, and usage. Size categories include big, medium, and small tunnels. Common shapes are circular, horseshoe, D-shaped, and rectangular. Usage includes water conduits, transport, storage, and mining. Factors considered for tunneling include suitable rock types, avoiding faults, minimum rock cover requirements, and ground conditions like soft ground, hard rock, and their impact on stability. Terminologies related to different parts of tunnels and tunneling conditions are also defined.
Geology is the study of the physical structure and substance of the Earth. It provides knowledge about construction materials like stones and clay. It also helps understand natural geological processes like erosion that impact civil engineering projects. Geology is important for determining suitable foundations, exploring ground conditions via drilling, and planning major projects like dams, roads and tunnels. The study of geology includes physical geology, petrology, structural geology, and the weathering of rocks. Physical geology examines how the Earth's surface and interior change over time. Petrology studies the origin, composition and structure of different rock types. Structural geology analyzes the three-dimensional distribution of rocks and their deformation history. Weathering breaks down rocks through mechanical and chemical processes.
This presentation discusses various ground improvement techniques, including:
- Dynamic compaction and dynamic replacement, which use heavy weights or tampers to densify soils.
- Vibro compaction and vibro replacement, which use vibratory probes to densify or install stone columns in soils.
- Controlled modulus columns, jet grouting, and vertical drains which are reinforcement techniques that install cement, soil-cement, or aggregate columns or improve drainage in soils.
- Menard vacuum consolidation, which uses a vacuum and vertical drains to accelerate consolidation of soft soils.
The document provides examples of applications of these techniques and their advantages for improving bearing capacity and reducing settlement of soils.
The document discusses various topics related to bridges including their purpose, importance, components, classifications, loadings, aesthetics, materials used such as steel and reinforced concrete, types of bridges like suspension bridges, causes of bridge failures, maintenance, and some landmark bridges in India. Bridges are structures built to provide passage over physical obstacles without closing the gap below and have been developing in sophistication since early human civilization. They are important for connecting difficult terrains, aiding trade and transportation, and reducing travel time.
Effect of underground tunnelling by (TBM) on foundations of existing structuresKishor Ade
This document discusses a dissertation on the effect of underground tunnelling by tunnel boring machine (TBM) on existing structures' foundations. It introduces the topic, provides a literature review on previous related studies, and outlines the methodology, which involves finite element modeling and analysis of shallow and raft foundations at different tunnel depths using Midas GTS NX software. The results found that tunnelling was suitable for raft and shallow foundations on hard and soft murrum soils when the tunnel crown depth was 20-25m below foundations, as displacements did not exceed code limits. Tunnelling was not suitable under shadu soil foundations.
This document provides an overview of stromatolites and microbial mat structures. It begins with definitions of stromatolites from early literature and discusses how understanding of these structures has evolved over time. It describes different classifications of stromatolites proposed by various researchers based on their morphology. The document also discusses microbial mat structures and reviews the distribution of stromatolites through geological time. It provides context on studies of Indian stromatolites, including those in the Vindhyan Basin, which are the focus of the project. The aim and objectives of the project to investigate the diversity and abundance of stromatolites and microbial mat structures in the Vindhyan Basin are also outlined.
metamorphic rocks and their distinguishing features-megascopic and microscopic study of gneiss, schist, quartzite, marble and slate
Properties and characteristics and uses of metamorphic rocks
Geology is the study of the Earth, including its origin, structure, composition and processes that have shaped it over time. It involves studying the Earth through observation, analysis and synthesis at locations like libraries, laboratories, museums and field sites. Geology is related to other sciences and has many branches of study. It is important to study geology because geological processes and resources influence human civilization, environments and hazards, and geology underpins engineering and understanding of landforms and Earth's history.
The document summarizes different techniques for retaining deep excavations, including contiguous piles, secant piles, sheet piling, diaphragm walls, soldier piles with lagging, and presents case studies of their use. It discusses techniques such as contiguous piles with soil anchors used for the IT Tower Lahore project requiring excavation to a depth of 65 feet, and contiguous piling with 9 layers of anchors for the Alamgir Tower Lahore project requiring excavation to 85 feet. It also summarizes the use of slurry walls for the large Washington Convention Center project requiring excavation up to 55 feet deep.
El documento describe los diferentes tipos de formaciones hidrogeológicas y sus características, incluyendo acuíferos, acuitardos y acuífugos. Explica que Honduras tiene varios tipos de acuíferos según su ubicación geográfica y composición geológica. Finalmente, concluye la importancia de entender las formaciones hidrogeológicas para evaluar el potencial y vulnerabilidad de los recursos hídricos subterráneos.
Este documento describe la ingeniería geotécnica y sus principales aspectos. La ingeniería geotécnica estudia las propiedades de los suelos y rocas para diseñar cimientos y estructuras. Un ingeniero geotécnico investiga las propiedades de los materiales en el sitio, evalúa riesgos como deslizamientos, y diseña cimientos y fundaciones apropiadas. Algunos logros notables de la ingeniería geotécnica incluyen el Taj Mahal, el túnel Seikan y el aeropuerto Chek Lap
Shallow foundations transfer structural loads to soil near the surface and are suitable when soil has good bearing capacity. They include spread, combined, and mat/raft foundations. Spread footings are most common, supporting individual columns or walls. Combined and mat foundations are used when loads overlap or are very high. Shallow foundations are simpler and cheaper than deep foundations but have limitations regarding soil conditions and structural loads.
Diagenesis is the process by which changes occur in sediment after it is deposited until the onset of metamorphism. During diagenesis, loose sediments are transformed into a solid rock through compaction, recrystallization, dissolution, replacement, cementation, and other processes. These diagenetic processes are important as they can significantly modify the composition and properties of the original sediment and even destroy sedimentary structures in rare cases.
FLUID INCLUSION WALL ROCK ALTERATION in economic geologyThomas Chinnappan
This document discusses fluid inclusions and wall rock alteration related to hydrothermal fluids. It defines fluid inclusions as tiny samples of trapped fluid in minerals, and describes hydrothermal fluids as underground hot water rich fluids capable of transporting metals. Wall rock alteration is defined as the reaction of hydrothermal fluids with enclosing rocks, causing mineralogical changes. The document outlines different types of wall rock alteration including potassic, phyllite, carbonatization, tourmalinization, greisenization, and silication alteration. It concludes that alteration phenomena are effectively studied in igneous rocks where progressive clay mineral alteration may occur.
Phd Thesis: Numerical modelling of surface subsidence associated with block c...Dr. Alex Vyazmensky
Through the use of an integrated FEM/DEM-DFN modelling technique this thesis presents a new approach to simulation of block caving induced surface subsidence allowing physically realistic simulation of subsidence development from caving initiation to final subsidence deformation. As part of the current research, a fundamental issue in modelling, the selection of representative equivalent continuum rock mass modelling parameters, is investigated and a procedure for calibration of modelling parameters devised. Utilizing a series of conceptual numerical experiments our fundamental understanding of the mechanisms and the role of the factors controlling block caving subsidence development is investigated. Valuable insights gained from this work are summarized in a preliminary subsidence classification and an influence assessment matrix of the governing factors. These are intended as an aid to engineering judgment for decision makers at the pre-feasibility and mine design stages.
This study also addresses one of the most challenging problems in mining rock engineering - the interaction between block cave mining and a large overlying open pit, focusing on caving induced step-path failure initialization. Using a novel approach to modelling data analysis a clear link between caving propagation, step-path failure development within the slope, and the resultant surface subsidence is established. In addition, FEM/DEM-DFN modelling is applied to the preliminary analysis of the block caving triggered slope failure at Palabora open pit.
This research represents a valuable contribution to block caving geomechanics and is a major step forward in the understanding of complex block caving subsidence phenomena, paving the way to more reliable assessment of caving induced subsidence deformations.
Tunnel and Underground Excavation PresentationChandan Pradhan
This document discusses tunnels and underground excavations. It defines different types of underground structures like tunnels, shafts, adits, and inclines. Tunnels are classified based on their size, shape, and usage. Size categories include big, medium, and small tunnels. Common shapes are circular, horseshoe, D-shaped, and rectangular. Usage includes water conduits, transport, storage, and mining. Factors considered for tunneling include suitable rock types, avoiding faults, minimum rock cover requirements, and ground conditions like soft ground, hard rock, and their impact on stability. Terminologies related to different parts of tunnels and tunneling conditions are also defined.
Geology is the study of the physical structure and substance of the Earth. It provides knowledge about construction materials like stones and clay. It also helps understand natural geological processes like erosion that impact civil engineering projects. Geology is important for determining suitable foundations, exploring ground conditions via drilling, and planning major projects like dams, roads and tunnels. The study of geology includes physical geology, petrology, structural geology, and the weathering of rocks. Physical geology examines how the Earth's surface and interior change over time. Petrology studies the origin, composition and structure of different rock types. Structural geology analyzes the three-dimensional distribution of rocks and their deformation history. Weathering breaks down rocks through mechanical and chemical processes.
This presentation discusses various ground improvement techniques, including:
- Dynamic compaction and dynamic replacement, which use heavy weights or tampers to densify soils.
- Vibro compaction and vibro replacement, which use vibratory probes to densify or install stone columns in soils.
- Controlled modulus columns, jet grouting, and vertical drains which are reinforcement techniques that install cement, soil-cement, or aggregate columns or improve drainage in soils.
- Menard vacuum consolidation, which uses a vacuum and vertical drains to accelerate consolidation of soft soils.
The document provides examples of applications of these techniques and their advantages for improving bearing capacity and reducing settlement of soils.
The document discusses various topics related to bridges including their purpose, importance, components, classifications, loadings, aesthetics, materials used such as steel and reinforced concrete, types of bridges like suspension bridges, causes of bridge failures, maintenance, and some landmark bridges in India. Bridges are structures built to provide passage over physical obstacles without closing the gap below and have been developing in sophistication since early human civilization. They are important for connecting difficult terrains, aiding trade and transportation, and reducing travel time.
1. Batardourile din palplanşe de lemn sunt de
forma unor pereţi verticali continui,
confecţionaţi din dulapi cu lăţimea de 15 - 25
cm, grosimea de 5-18 cm şi lungimea
limitată la 7 - 9 m.
Pentru a corespunde din punct de vedere
al etanşeităţii, palplanşele se îmbină prin
prelucrarea laturilor (fig. 6.10), vârful
palplanşei se prelucrează prin ascuţire, şi
anume simetric pe cele două feţe laterale şi
asimetric dinspre muchia prelucrată cu lamb,
pentru ca prin batere, componenta orizontală
a rezistenţei terenului să permită strângerea
palplanşelor una de cealaltă. În timpul
baterii, capul palplanşelor se protejează cu o
căciulă metalică, vârful palplanşei se
protejează cu un sabot metalic.
Operaţia de înfigere (fişa) palplanşelor
cuprinde:
• nivelarea terenului şi trasarea ecranului;
2. • baterea unor piloţi în colţuri şi în
aliniament la distanţe de 3 - 5 m unul de
altul, prevăzuţi cu ulucuri de forma celor
executate la palplanşe;
• montarea unor cleşti între capetele
piloţilor la distanţă de 0,4 - 0,5 m deasupra
terenului pentru ghidarea palplanşelor.
Deschiderea dintre cleşti este cu 1 - 2 cm mai
mare decât grosimea palplanşelor (fig. 6.11);
• fişa palplanşelor se realizează pe
intervalul dintre doi piloţi, prin batere cu un
berbec uşor (circa 200 kgf) sau prin vibrare.
Fig. 6.10. Palplanşe din lemn
3. După natura terenului ele se înfig câte una
sau câte 2 - 3 simultan; înfigerea începe cu
palplanşa din capătul indicat de sensul de
ascuţire al vârfului şi se execută până la
adâncimea de 1,5 - 2 m pe tot pasul dintre
doi piloţi; în continuare ele se înfig în trepte
de câte 0,5 - 1,0 m.
Batardoul din palplanşe de lemn constă
din unul sau două rânduri de palplanşe, cu o
umplutură de pământ spre partea opusă
presiunii. Batardoul dintr-un singur perete de
palplanşe (fig. 6.12) are înălţimea maximă de
5,0 m. Peretele este executat din palplanşe
introduse în teren la o adâncime de 2,0 m în
terenuri tari şi la 3,0 - 4,0 m în terenuri
nisipoase. Pentru stabilitatea peretelui, în
funcţie de înălţimea sa, se aşează una sau
două rânduri de contrafişe, la distan]e de 2 -
3 m, care reazămă în ţăruşi bătuţi în pământ.
4. Batardoul format din doi pereţi de
palplanşe (fig. 6.13) are înălîimea maximă de
8,0 m. Distanţa dintre pereţi trebuie să fie
mai mare decât adâncimea maximă a apei.
Fig. 6.11. Înfigerea palplanşelor din lemn
Fig. 6.12. Batardou cu un singur
perete de palplanşe din lemn
5. Fişa pereţilor este de 3 - 5 m, fiind realizaţi
din dulapi de 10 - 18 cm şi piloţi de 25 - 27
cm. Pereţii din palplanşe se rigidizează la
partea superioară cu moaze din rigle, aşezate
la distanţe de 2 - 3 m; la înălţimea nivelului
de lucru al apei se montează buloane de
strângere φ 25 - 40 mm. Spaţiul dintre pereţi
se umple cu pământ argilos sau cu pietriş
conţinând şi nisip fin. În partea exterioară a
peretelui, care preia presiunea apei, se face o
umplutură pe o înălţime care depăşeşte cu
circa 0,5 m nivelul de lucru al apei.
Fig. 6.13. Batardou cu
doi pereţi de palplanşe
din lemn
6. E. Palplanşele metalice se folosesc la
lucrări de izolare a unor incinte de lucru în
apele adânci, pentru realizarea unor pereţi
etanşi, sau pentru sprijinirea săpăturilor cu
adâncime mare.
Palplanşele metalice se execută din
oţeluri care au elasticitate şi rezistenţe
mecanice mari, fiind totodată şi rezistente la
coroziune. Profilurile de laminare sunt foarte
diferite, urmărindu-se mărirea rezistenţei la
încovoiere, precum şi satisfacerea cerinţelor
tehnologice şi funcţionale. Palplanşele
metalice pot avea lăţimea de 22 - 42 cm,
înălţimea profilului de 3,5 - 44 cm, lungimea
de 2,5 - 35 m şi grosimea peretelui de 4 - 23
mm. În mod frecvent se folosesc (fig. 6.14)
Fig. 6.14. Palplanşe metalice
7. profilele I (Lackwanna sau Senelle), profilul
S sau Z (Rombas), sau profilul U (Larsen).
Pentru realizarea unor unghiuri mai mari de
20° la ecranele din palplanşe metalice,sunt
necesare palplanşe de formă specială, livrate
de industrie sau executate pe şantier.
Pentru înfigerea palplanşelor metalice se
folosesc sonete cu berbeci sau vibratoare. În
timpul înfigerii ele sunt ghidate la două
nivele. Astfel, o pereche de cleşti trebuie să
fie localizată cât mai jos posibil, fie la nivelul
terenului, fie imediat deasupra nivelului
minim al apei. În ape cu curenţi puternici
este necesar să se fixeze cleşti şi la nivelul
fundului albiei. Pentru executarea lucrărilor
în apă, sonetele pot fi montate pe pontoane a
căror stabilitate se asigură fie prin ancorare,
fie prin coloane de papionaj.
8. F. Batardourile din palplanşe metalice
pot fi dintr-un perete simplu, din pereţi dubli
sau batardouri celulare. Batardourile simple
sunt alcătuite dintr-un singur perete din
palplanşe metalice, de tipul unei diafragme
de etanşare, şi un corp realizat din umplutură
de pământ, balast sau anrocamente.
Batardourile cu pereţi dubli din palplanşe
se folosesc în cazul unor cursuri de apă cu
adâncimi de până la 12 m (fig. 6.15). Ele
sunt alcătuite din două rânduri de pereţi,
solidarizaţi cu ajutorul unor tiranţi din oţel,
montaţi la distanţe de 2 - 3 m. Spaţiul dintre
pereţi se umple cu agregate sau pământ. În
Fig. 6.15. Batardou cu pereţi dubli din
palplanşe metalice
9. scopul măririi siguranţei în exploatare, la
baza peretelui dinspre incintă se execută o
umplutură prevăzută cu un sistem de drenaj.
Acest tip de batardouri se execută mai rar.
Batardourile celulare din palplanşe
metalice se folosesc pentru izolarea unor
incinte de lucru situate în albiile râurilor, în
scopul executării unor construcţii
hidrotehnice, putând însă constitui şi
construcţii definitive ca: ziduri de sprijin,
cheiuri portuare etc. În general se folosesc
pentru adâncimi ale apei de 15 - 20 m şi
viteze de scurgere de 4 - 5 m/s.
Batardourile celulare sunt formate din
compartimente realizate din palplanşe
metalice şi umplute cu nisip sau balast, prin
sedimentare cu ajutorul hidromecanizării. Ele
sunt de două tipuri: batardouri cilindrice şi
batardouri-segment (fig. 6.16).
10. Batardourile celulare cilindrice sunt mai
frecvent utilizate, fiind mai sigure, întrucât
cedarea unei celule nu antrenează distrugerea
celorlalte. Deasemenea, la acest batardou,
umplerea celulelor se face astfel, ca diferen]a
de nivel a umpluturii între două celule vecine
să nu depăşească 2,0 m. Asemenea
batardouri s-au utilizat la execuţia SHEN
Porţile de Fier I.
Batardourile celulare sunt construcţii
autoportante în cazul terenurilor stâncoase.
Pe terenurile de fundare nisipoase se execută
încastrarea palplanşelor în teren, pentru
asigurarea stabilităţii. La Porţile de Fier I,
Fig. 6.16. Batardouri celulare din palplanşe metalice
11. palplanşele au fost încastrate pe o adâncime
de 0,4 m în roca de bază constituită din
marne calcaroase.
Montarea palplanşelor pentru realizarea
celulelor se poate executa de pe o platformă
plutitoare autoridicătoare (fig. 6.17), sau de
pe o estacadă special construită. Platforma
plutitoare în formă de U este prevăzută cu 4
piloni metalici, o macara pentru deplasarea
palplanşelor şi celorlalte utilaje, precum şi
echipamentul de lucru.
G. Etanşările cu palplanşe din beton
armat se folosesc în cazul lucrărilor
definitive, unde ecranele din palplanşe au de
preluat sarcini mari şi sunt expuse apelor
agresive.
În general palplanşele din beton se
armează puternic cu armătură longitudinală
şi etrieri, şi sunt prevăzute cu lamb şi uluc
pentru realizarea îmbinărilor (fig. 6.18).
12. Datorită masei mari, palplanşele din
beton armat sunt puţin deviate în timpul
înfigerii, ceea ce face să se renunţe uneori la
joantele de îmbinare, obţinându-se o etanşare
Fig. 6.17. Platformă plutitoare autoridicătoare pentru realiyarea batardourilor
celulare
Fig. 6.18. Palplanşe din beton armat
13. satsfăcătoare după înfigere, prin umplerea cu
mastic bituminos a unor canale prevăzute pe
suprafeţele de contact. Vârful palplanşelor
din beton armat este ascuţit asimetric pentru
a genera împingerea spre palplanşa vecină în
timpul baterii.
Procesul de înfigere în teren a acestor
palplanşe se execută prin batere cu ajutorul
berbecilor. Pentru a se evita deteriorarea
betonului în timpul baterii, capul
palplanşelor se protejează cu o pernă
metalică.
Din cauza volumului şi greutăţii mari,
palplanşele din beton armat impun condiţii
speciale pentru transportul şi punerea lor în
operă, necesitând utilaje de mare capacitate.
6.3. Scoaterea palplanşelor
14. Avantajul major al folosirii palplanşelor,
în cazul utilizării lor la lucrări provizorii,
constă în posibilitatea de refolosire. Pentru
aceasta este necesară îndeplinirea a două
condiţii:
• pe de o parte, nu pot fi scoase decât cu
condiţia ca această operaţie să nu prezinte
riscuri pentru stabilitatea lucrărilor
învecinate;
• pe de altă parte, nu pot fi scoase decât
în condiţii economice avantajoase, sau altfel
spus, cu condiţia ca la scoatere palplanşele sa
nu fie deformate sau rupte, fiind posibilă
refolosirea lor.
Posibilitatea de scoatere şi recuperare
depinde în mare măsură de modul în care
palplanşele s-au pus în operă: astfel,
palplanşele dintr-un rând, care au fost bătute
cu uşurinţă, sunt mult mai uşor de extras ca
acelea dintr-un rând care au ajuns dificil la
cotă şi care pot fi răsucite, deviate şi chiar
15. înfăşurate, sau materialul din zona capului
palplanşei fiind obosit, apare deseori ruperea
din cauza consumului exagerat de energie la
batere.
În cazul în care palplanşele au o perioadă
îndelungată de serviciu în anumite lucrări (de
exemplu batardouri), durată ce depăşeşte de
regulă 3 ani, în soluri pulverulente cu matrice
argiloase şi care ulterior au devenit puternic
compactate şi saturate cu apă, posibilitatea de
scoatere se diminuează întrucât, în timp,
coeziunea moleculară a format în jurul
rândului de palplanşe o zonă de mare
densitate, aderentă la palplanşe (prismă de
coeziune). Din această cauză, la extragere
această prismă aderentă la palplanşă este
antrenată odată cu palplanşa, necesitând forţe
suplimentare de smulgere şi uneori tehnici
speciale de distrugere a coeziunii.
Procedee utilizate: în cazul palplanşelor
scurte (4 - 5 m), introduse uşor într-un sol
16. moale sau de consistenţă redusă, este posibil
a utiliza direct forţa de tracţiune a unei
macarale, dar în majoritatea cazurilor, vom
avea nevoie să recurgem la forţe
suplimentare de tracţiune şi de maşini special
adaptate pentru scoatere, numite extractoare.
Principalele tehnici care sunt folosite
sunt: batere, vibrare şi procedeul combinat
sub jet de apă (lansajul).
Aceste tehnici, care sunt aplicate în mod
curent, sunt asemănătoare cu cele de înfigere
numai în ceea ce priveşte scopul principal,
iar deosebirile constau în modul de lucru al
utilajelor.
A. Procedeul prin batere este identic cu
procedeul de la introducerea palplanşelor,
doar că baterea se efectuează în sensul de
extragere a palplanşelor, bineînţeles cu
anumite modificări ale utilajelor, modificări
care pot fi constructive, sau în unele cazuri
17. făcute pe şantier. Pentru realizarea acestui
procedeu se folosesc următoarele tipuri de
extractoare:
• Extractoare cu aer
comprimat - sunt ciocane
vibratoare, aceleaşi care sunt
folosite la înfigere, şi care sunt
montate răsturnat şi echipate
special (fig. 6.19). Printre
constructorii care preferă acest
sistem sunt cei de la firmele
PAJOT şi TIFINE. Alte firme,
ca de exemplu DEMAG, au construit
extractoare care funcţionează conform
aceluiaşi principiu, dar din concepţie s-a
prevăzut ca aceste utilaje să fie folosite
numai pentru extragerea palplanşelor (fig.
6.20).
Fig. 6.19. Ciocan
vibrator echipat pentru
extragere
18. Aceste extractoare sunt în
general constituite dintr-un
piston fix, solidarizat cu un
dispozitiv de prindere, pe
care culisează un cilindru.
Ridicarea cilindrului se
realizează prin introducerea
aerului comprimat, îar
căderea este liberă. În cursa sa ascendentă
cilindrul loveşte pistonul, transmiţând
palplanşei energia de recul. Partea superioară
a extractorului este echipată cu o suspensie
cu arcuri, iar partea inferioară cu un
dispozitiv de prindere a palplanşei.
Aceste utilaje funcţionează cu aer
comprimat, au o cadenţă de batere cuprinsă
între 160 - 350 lovituri/minut, greutăţi între
100 - 4300 kgf şi permit obţinerea unor
energii de lovire peste 1000 kgm.
Fig. 6.20. Extractor special cu
aer comprimat
19. Pentru a obţine un randament ridicat de
scoatere, trebuie exercitată
o forţă de tracţiune cel
puţin egală cu de 3 ori
greutatea extractorului;
acest raport poate ajunge
la 5 în cazul extractoarelor
de greutăţi mici. Greutatea
maşinilor utilizate trebuie
să fie în general puţin
superioară greutăţii
palplanşelor de extras.
• Extractoare Diesel - există destul de
multe extractoare de acest tip, ele sunt
constituite dintr-o tijă de extragere care
ghidează o masă de lovire, acţionată prin
intermediul bielelor de două pistoane
Fig. 6.21. Extractor Diesel
20. înclinate. Când masa de lovire coboară, cele
două pistoane comprimă aerul conţinut în
cilindri, iar combustibilul injectat este aprins.
Gazele de combustie trimit în sus masa de
lovire, prin intermediul pistoanelor şi bielelor
şi care, lovind un tampon, transmite energia
de şoc la palplanşe prin intermediul tijei de
extragere (fig. 6.21).
Extractoarele Diesel sunt suspendate în
cârligul macaralei cu ajutorul unei suspensii
cu resort. Aeste utilaje pot atinge greutăţi de
2400 kgf (fără accesorii), dezvoltă energii de
batere de 500 kgm, necesitând o forţă de
tracţiune la cârligul macaralei cuprinsă între
10 şi 20 tf. Cadenţa de lovire este cuprinsă
între 100 şi 130 lovituri/minut şi se pot
utiliza la extragerea palplanşelor cu greutăţi
cuprinse între 2000 şi 2500 kgf.
B. Procedeul prin vibrare - folosit pentru
introducerea palplanşelor în sol, poate fi
21. integral utilizat în scopul extragerii,
exercitându-se o forţă suplimentară de
extragere cu ajutorul macaralei. Acest
procedeu este utilizat mai cu seamă atunci
când la punerea în operă a palplanşelor a fost
folosită tehnica vibroînfigerii. Palplanşele
înfipte prin vibrare pot fi întotdeauna scoase
cu acelaşi procedeu, cu excepţia terenurilor
care după înfigere au fost foarte bine
compactate, sau a terenurilor care prezintă
fenomene de tixotropie.
Tracţiunea utilă la cârligul macaralei
poate fi de 2 (pentru extractoare grele) la 4
ori greutatea vibratorului şi a palplanşei. Este
indispensabil de a interpune un grup
amortizor între vibrator şi cârligul macaralei,
pentru a opri transmiterea vibraţiilor la cablul
macaralei, grup format din arcuri elicoidale
sau tampoane de cauciuc.
22. C. Procedeul combinat, sub jet de apă,
foloseşte vibroexportatoare. Această tehnică
este o combinare a uneia din procedeele
descrise mai sus, cu procedeul de lansare
folosit la introducerea palplanşelor în teren,
cu diferenţa că jetul de apă decompactează şi
afânează terenul pentru a micşora frecarea
între palplanşă şi teren, sau de a rupe
coeziunea dintre teren şi palplanşă.
Procedeul combinat foloseşte acelaşi
echipament ca la lansare, adică pompă,
racorduri flexibile şi lance, dar scoaterea se
face în două etape: decompactarea cu jet de
apă în lungul rândului de palplanşe înfipte, şi
extragerea cu unul din procedeele descrise
anterior.