软土真空预压法加固效果分析

Analysis of Reinforcing Effect on Soft Clay by Using Vacuum Preloading Method

本文以缅甸某真空预压工程为依托,研究了真空预压等地基处理方法对缅甸软黏土层的加固效果。在真空预压前后,分别对各个钻孔的土样进行室内土工试验以及现场的标准贯入试验,再进行对比分析,研究真空预压法的加固深度和效果。得出以下结论:真空预压对缅甸软黏土有较强的加固效果,含水率、孔隙比、压缩系数变小,内聚力、内摩擦角、压缩模量、标贯击数变大,加固深度最大可达到地表以下19 m左右;而在加固深度范围内,其加固的效果随着深度的增大而不断衰减;真空预压对软黏土层加固,其含水率与孔隙比降低了10%~15%左右,压缩模量提高了15%~40%左右,标贯击数提高了50%~60%左右;另外,软黏土层中的淤泥质黏土层经过加固后定名变化为黏土,效果明显。

A Myanmar vacuum preloading project is selected to study the effect on local soft clay layer by using vacuum preloading method,including lab geotechnical tests of soil samples gathered from boreholes and field SPT test before and after vacuum preloading,comparative analysis of the above data as well as reinforcing depth and effect.It is concluded that vacuum preloading has better reinforcement effect on soft clay layer in Myanmar,Basically meet the requirements for smaller coefficients involving water content,void ratio and compression,larger cohesion,internal friction angle,compression modulus and SPT blow number,among which,the maximum reinforcing depth can be approx.19 m below ground.Within the range of depth,the reinforcing effect decreases with incremental depth.The application of vacuum preloading method lowers water content and void ratio of soft clay layer by 10%~15%,increases its compression modulus and SPT blow number by 15%~40%and 50%~60%respectively.In addition,the reinforced mucky clay in the soft clay layer is redefined as clay,which shows significant effect.