随着地下空间的大力开发，基坑降水导致的地面沉降对周边建筑物稳定性及地下管道系统产生一定影响，开始引起国内外学者的关注。本文选择武汉地区典型粉土，采用土－水特征曲线压力板仪开展失水过程的土－水特征曲线试验，得到了非饱和土的土－水特征曲线；质量含水率、轴向位移随基质吸力的变化规律及误差修正；不同基质吸力作用下含水率和轴向位移随时间的变化规律。根据测定曲线，非饱和土含水率随基质吸力的增大而减小，达到残余含水率时不再变化；随着基质吸力的增加，土体失水收缩，轴向位移增大，达到残余含水率时不再变化；加压过程中不仅有轴向变形，还伴随有一定径向变形。除此，对仪器本身及试验过程中可能出现的误差进行了详细的分析，为压力板仪试验提供参考依据。%With the vigorous development of underground space,the ground settlement caused by dewatering has an impact on the stability of surrounding buildings and underground piping systems,which has attracted attentions of domestic and foreign scholars.This article uses typical silt of Wuhan to carry out dehydration process of SWCC test with the pressure plate apparatus.The following results are obtained:SWCC of unsaturated soil;mass moisture content,the axial displacement variation with the change of matric suction and their error correction;water and axial displacement variation with time under different matric suction.According to the measured curve,the water content of the unsaturated soil is reduced with the increasing matric suction before it reaches the residual moisture content;the soil shrinks because of water loss.The axial displacement increases with the increasing matric suction., at a residual moisture content,axial displacement increase stops changing.During pressurization,axial deformation appears,accompanied by a certain degree of radial deformation.In addition,a detailed analysis is carried out about the instrument itself and the error that may occur during the test,which provides a reference to the pressure plate test.
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