Analysis of Laterally Loaded Long or Intermediate Drilled Shafts of Small or Large Diameter in Layered Soil
Strain wedge (SW) model formulation has been used for evaluating the response of a single pile or a group of piles in layered soils to lateral loading. The SW model approach provides appropriate prediction for the behavior of an isolated pile and pile group under lateral static loading in layered soil (sand and/or clay). In this study, the authors extend the capability of the SW model to predict the response of laterally loaded large diameter shafts considering 1) the influence of shaft type on the lateral shaft response; 2) the nonlinear behavior of shaft material and its effect on the soilshaft-interaction; 3) developing partial or complete liquefaction in the surrounding soil profile based on far and near-field induced porewater pressure; and 4) vertical side shear resistance along the shaft wall that has a significant contribution to the lateral shaft response.
Penetration Tests and Bearing Capacity of Cohesionless Soils
From comparison between standard (dynamic) and static penetration resistances on number of sites, simple approximate correlation has been obtained to estimate relative density and angle of internal friction; proposed relationships applied to determine ultimate bearing capacity of footings and point resistance and skin friction of piles; results compared with field loading tests on plates and piles.
Liquefaction Evaluation Procedure
A procedure for evaluating liquefaction susceptibility of a soil mass subjected to shear stress, such as in slopes, embankments, and foundations of structures, is presented. Liquefaction analysis is a stability analysis for which the shear strength in the numerator of the factor of safety equation is the undrained steady-state strength, and the denominator is the driving shear stress. The driving shear stress is the shear stress required to maintain static equilibrium. The undrained steady-state shear strength is a function only of the void ratio. Thus, one critical step of the procedure for liquefaction evaluation is the determination of the in-situ void ratio and the correction of laboratory-measured undrained steady-state strength to account for unavoidable changes in void ratio of the soil during sampling and testing. Dilative soils are not susceptible to liquefaction. Cyclic load tests are not required to evaluate the susceptibility to liquefaction.