Analysis Of The Catastrophe Due To Foundation Treatment In Soft Clay District

The structure and shear strength of soft clay is destroyed and reduced under exterior disturbance which makes soil into fluid without strength. There is a lot of additional settlement occurring during the recovery process of the structure and strength of soft clay with time. Due to the serious damage effect of disaster, research on the characteristic of soft clay affected by foundation treatment, the disaster mechanism analysis of foundation treatment and measures to avoid the destroy of soft clay are meaningful. Based on field test and theory analysis, the main conclusion were as followings:The test of pore pressure and lateral earth pressure, static cone penetration test and settlement observation during soft foundation treatment process were used to analysis the strength thixotropic and the degree of thixotropic caused by cement mixing pile construction.The main reason leading to mixing pile sinking is that pore water pressure is larger than the earth pressure during piling. Large porous, the weak bond between soil particles and the "short-range power effect" between soil particles are the internal factors of thixotropic. Other factors such as temperature, salt concentration, charge and water content also affect the thixotropic of soft clay. The structural dynamic model and multi-dimensional virtual model were used to simulate the process of soft clay thixotropic.Combined with the formula of reaming radius considering grouting volume, grouting pressure and soil parameter, the circle shear expansion model was used to predict the excess pore pressure and lateral displacement. Three judging methods based on stress and strain were introduced to judge the grade of disaster.Based on contrast test results, the suitable mode, sequence and velocity of construction, the appropriate pile spacing were some effective methods for the prevention of soft clay disaster.