季节性冻土中土工格栅加筋特性试验研究

针对东北地区典型粉质黏土,通过一系列土工格栅在冻土中的拉拔试验,重点分析了土壤含水率及冻融循环作用对土工格栅加筋性能的影响,并基于拉拔摩擦强度、表观摩擦系数、界面摩擦阻力和端承被动阻力等理论,对试验数据进行了详细分析。研究发现:含水率对土工格栅加筋效果存在明显抑制作用,含水率从20%提高至32%时,筋土界面摩擦阻力和端承被动阻力均减小60%以上。而当含水率一定时(w=24%),冻融循环作用反而提高了土工格栅的加筋效果,经历7次冻融循环后,土工格栅加筋效果增幅为30%左右,主要是横肋前端承被动阻力的提高,而筋土间界面摩擦阻力变化不大。上述试验成果可为土工格栅在冻土地区的推广应用提供一定的理论依据。

Experimental investigation on reinforced characteristics of geogrids in seasonal frozen soil

A series of pullout tests to investigate the reinforced characteristics of geogrids in frozen soil are conducted in the laboratory under various moisture contents and different freeze-thaw cycles. Based on the theories about frictional strength, apparent friction coefficient, interface frictional resistance and passive resistance, the test data are analyzed. Some conclusions are drawn that the moisture content can obviously inhibit the effect of reinforcement. The interface frictional resistance and passive resistance both decrease to 40% while the moisture content increases from 20% to 32%. Then the moisture content is constant to 24%, the freeze-thaw cycles can improve the reinforcement effect of geogrids. Mainly for the passive resistance has a certain extent enhancement, but the interface frictional resistance nearly has no change. The experimental results are of referring value for the design of geogrids-reinforced earth structures.