Field test research for optimization design under condition of complex Soil Stratum

It is highly important to choose suitable of the foundation in underground engineering. With the engineering, the foundation is made of gravelly soil, which distributed discontinuity and had bad uniformity. Drilling method, dynamic sounding method and deep plate loading test were applied, combined with previous investigation results, geotechnical parameters were defined and optimization designed. Upon the result of field tests, some control measures were made to improve the condition of foundation .District control measures were suggested to be made. The silt clay layer④under the basement of 1 # building's east A- area, pile pier was suggested to be set up, the pier's bottom should be set in cement gravel⑤strata, and should made of C15 plain concrete, raft foundation should also be applied. In other areas, soil upon cement gravel⑤strata were suggested to be dig out, and replaced with rubble concrete to the level of foundations bottom, also should applied raft foundation. Foundation strength and deformation were up to the mustard according to the result of numerical simulation. The optimization design not only supplied the technical demand well, but also reduced a lot of construction schedule and save cost. This study supplied some theory and technical guides to closely engineering.