中-强膨胀土竖向膨胀力原位试验

摘要

利用平衡加压法在云桂高速铁路典型中-强膨胀土路段进行竖向膨胀力原位试验，研究竖向膨胀力随时间、含水率增量、卸荷回弹量的变化规律，并对试验过程中试验体周边地表的变形进行了监测。结果表明：竖向膨胀力随时间的变化规律与膨胀土中渗水通道的畅通情况密切相关；竖向膨胀力随含水率增量的变化规律可分为4个阶段，即初始线性增长阶段→过渡阶段→二次线性增长阶段→稳定阶段；卸荷时，膨胀土竖向回弹变形增加，竖向膨胀力不断减小，二者呈线性或二次曲线性变化；试体周边地表的隆起规律与竖向膨胀力随含水率增量的变化规律相一致。%With the swelling pressures balancing method,in-situ vertical swelling pressure tests were made in typical mid & strong expansive soil sections of the Yun-Gui High-speed Railway to study the law of change of vertical swelling pressures with time,dampness increments and decompression rebound amounts and to moni-tor ground surface deformations surrounding the specimen in the test processes.The results show as follows:The law of changing of vertical swelling pressures with immersion time is closely related to the penetrating pas-sage situation of weeper drains;changes of vertical swelling pressures with dampness increments can be divided into four stages,i.e.,the initial linear increasing stage,gradual transition stage,second linear increasing stage and stabling stage;when unloading,vertical rebound deformations increase in the shape of the linear or quad-ratic curve whereas vertical swelling pressures keep on decreasing;the upswelling law of ground surface sur-rounding the specimen is consistent with the changing law of vertical swelling pressures with dampness incre-ments.