Experimental Study Between Laterally Loaded Piles And Degraded Saturated Fine Sands

Under seismic loads, integral pore water pressure in stratum will increasecontinually, and as a result the stratum become degraded saturated. Though thestratum hasn't come to liquefied standard, it will produce hazard to pile foundation,and even affect the regular service. In engineering design, it's necessary to consideratethe impact of degraded stratum on foundation stability. It has engineering applicationvalue to evaluate lateral bearing capacity of piles in liquefied standard. Therefore, theresearch on the contents mentioned above is very utility and necessary.Firstly, In accordance with the method of reference two that the residual porewater pressure was maintained by applying the back pressure to the saturated sandstratum, a model test method was developed to simulate the interaction of pile andsaturated sands with the excess pore water pressure from seismic loads. Model tests ofthe soil-pile interaction corresponding to different degradation state strata wereconducted using fine sand and test devices concerned in reference two.The rules ofparameters of ultimate lateral resistances, lateral resistance and modulus coefficientthat changed with the residual pore water pressure in saturated sand was analyzedthrough the soil and pile p-y curves of degraded saturated strata.getting from modeltests,and contrastive analysising with the model tests results using inorganic silt–finesand concerned in reference two, discussing the influence that sand nature to theseparameters.Secondly, Making remoulded sample in the same relative density using the samefine sand in these model tests. Triaxial tests were done to determine the intensiveparameters in different degraded saturated status. Researching the method todetermine the ultimate lateral resistances based on the sand intensive parameters onthe consideration that there have overlying pressure on the surface of the sandreferencing to the failure mode suggested by Reese in reference two. Determining thetheoretical value of ultimate lateral resistances in different degradation state of thesaturated sand stratum In accordance with this method and the sand intensiveparameters, then having a comparison with the actual measures in the model tests andresearching the relationship of ultimate lateral resistances between actual value andtheoretical value.Finally, using fine sand, in the conditions of specific residual pore water pressure,the dynamic and static model tests were done on small shaking table and theexperimental results were contrasted to verify that the model test, which can simulatethe saturated sands become degraded with the residual pore water pressure fromseismic loads by applying the back pressure to the saturated sand stratum tomaintenance specific residual pore water pressure, was appropriate.