The effective controlling measuresmust be adopted in bored pile construction at quicksand and soft soil layer, which can reducef engineering accidents and assure engi-neering quality.

The side scan sonar, dual frequency echo sounder and subbottom profiler were used to make acoustic surveys of soft bottom sediments in the Chengdao sea area, the interfaces between fluid mud, soft soil layer and sea bottom and the thicknesses of fluid mud and soft soil lay.

Since the topsoil in Zhujiang Delta area is the silt soft soil of the 4th-system marine deposit,the foundation pit supporting forms of high-rise buildings become the vital technological links in the building project.

In this artick the author analyses the engineering anti-seismic of water and lake sediments soft clay around Jun shan area,points out the part which lique faction can easily happen in silty sand and muckey silty clay and puts forward corresponding precautions against earthquakes.

Analogue analysis for relationship between leaking water amount and settlement of tunnels in soft soil stratum;

The application of deep-mixing pile water-resisting curtain in soft soil stratum construction;

A study on the secant pile endosure structure techology in soft soil stratum of Shanghai;

The application of the combined pile and anchor retainingstructure for deep excavation engineering in soft soil;

Based upon analysis of overturning failure of composite soil nailing wall retaining system of foundation pit of one office in Suzhou one conclusion is obtained that foundation pit is subject to instable when soil mass work encounter soft soil layer and with high water content utilizing composite soil nailing wall for foundation pit support.

The technical process of tamping macadam compaction pier is as follows: firstly form pores artificially,then replace the soft soil with the scree and tamp to close-grained scree pier by layered power.

Taking soft foundation treatment in Wengang Road widening reconstruction engineering in development zone of Yancheng as an example,the author introduces the construction technological process of strengthening soft soil layer with wasted granular materials and the control essentials of each working procedure,and points out construction notices,in order to achieve well strengthening result.

Through the illustration of actual engineering practices, it points out that the subsidence characteristics caused by the soft soil layer under the roadbed is closely related to the buried depth.

The main target of this thesis is as follows:1、Study the influence of the soft soil layer to peak acceleration of earthquake, mainly study the thickness and depth of the soft soil layer to analysis the amplification effect or reduction effect of peak acceleration of earthquake.