1. DEEP EXCAVATION &DEEP EXCAVATION &DEEP EXCAVATION &DEEP EXCAVATION & EARTHEARTHEARTHEARTH RETAININGRETAININGRETAININGRETAINING
STABILISTABILISTABILISTABILIZZZZING STRUCTURESING STRUCTURESING STRUCTURESING STRUCTURES
PREPARED BY : THANUJAN. T

2. CONTENTSCONTENTSCONTENTSCONTENTS
Earth Pressure Theories………………………………………..……... 1-16
1. Earth Pressure Theory………………………………………………........…... 1-2
2. Rankine Method………………………………………………………...……. 3-7
Active condition for c-f soil
Active condition for Su material
Rankine earth pressures for non-vertical wall & slopping backfill
3. Coulomb Method……………………………………………………………… 8-9
4. Water Pressures due to seepage behind the wall……………………………. 10-11
5. Short term Vs Long term response – Stress path…………………………... 12-16
Retaining Structures…………………………………………………… 17-29
1. Rigid Retaing Structures……………………………………………………... 18-21
Sliding or Translational failure
Rotational failure
Bearing capacity failure
Deep seated failure
Seepage induced instability
2. Design Examples based on BS and Eurocode……………………………….. 22-30
Gravity retaining wall
Cantilever retaining wall
3. Flexible Retaining structures…………………………………………………. 31-37
Cantilever sheet pile wall
Single propped or Anchored walls
Finite Element Modelling of Excavations…………………………….. 38-46
1. Modelling of Drained Excavation using Plaxis………………………………. 38-39
2. Modelling of Undrained Excavation using Plaxis……………………………. 39-46
Undrained A
Undrained B
Undrained C
Description of stress path for undrained A, B & C

3. Stability Issues in Excavation Support System………………………. 47-46
1. Basal Heave Failure……………………………..………………………………. 47-53
Rankine theory (Lower bound)
Coulomb theory (Upper bound)
Base stability of circular shaft in soft CLAY
Summary of Basal heave equations
2. Hydraulic Failure (Piping)……………………..………………………………… 53
3. Slurry Wall Design………………………………………………………………... 53
4. Hydraulic Uplift…………………………………………………………………… 54