振弦式孔隙水压力计在真空预压工程中的长期工作性能

Long term working performance of vibrating wire piezometers in vacuum preloading engineering

真空预压是一种在大面积深厚软黏土地基处理中有着广泛应用的排水固结方法。为获得地基加固过程中土体的固结度增长和变形情况,需要对真空预压过程进行监测。孔隙水压力是其中一项重要的观测项目,能够直接反映超静孔隙水压力的消散情况。孔隙水压力计主要分为开放式和密闭式两大类,对两种类型孔隙水压力计的测量原理进行分析,并通过现场试验对真空预压中常用的振弦式孔隙水压力计测头工作性能进行分析,提出提高长期稳定性及准确性的措施,包括采用饱和的致密的透水石和Ridley-type可冲刷的振弦式孔隙水压力计。

Vacuum preloading is an effective consolidation method to treat thick soft clay.In order to measure the increase of consolidation and the deformation change during the ground improvement,the consolidation process should be monitored.The pore water pressure is an important parameter to indicate the dissipation of excess pore water pressure.Piezometer can be divided into two types,open and sealed respectively.The measuring principles of open and sealed piezometers are analyzed,the performance of vibrating wire piezometer in vacuum preloading is checked by field trial tests,and the methods to improve the long term robustness and accuracy of vibrating wire piezometer are proposed,including adopting filter stone with high air enter value and Ridley-type flushable piezometer.