膨润土防渗毯用于渠道衬砌及其老化因素对力学性能的影响

摘要

膨润土防水毯(GCL)在渠道衬砌工程有较大的应用价值.为了测试膨润土防渗毯用于渠道衬砌其老化因素对力学性能的影响,以内蒙古河套灌区为研究区域,采用室内模拟及工程现场试验相结合,对5种老化因素的3种GCL力学性能影响进行了测试.结果表明:温度、湿度、紫外线照射都会对GCL的力学性能造成影响.高温对GCL力学性能影响大于低温,高低温循环对G-CL力学性能影响小于高温或低温单独的影响.60℃高温老化72 h,3种试样力学性能值(最大荷载)降低了34.27％、35.77％、45.02％;-40℃低温老化72 h,降低了19.51％、31.49％、18.40％；高低温循环10次(低温-40℃下保持12h,高温60℃下保持12h),降低19.32％、32.62％与38.28％.紫外线照射1 200h,降低了29.08％、18.31％与36.17％.GCL含水率从50％增加到100％在60℃下老化24 h,2#与3#的力学性能值下降12.41％、13.08％,1#没有变化.野外GCL第1年老化速度较快,3试样力学性能值下降12.1％、18.5％和17.8％,1年后力学性能变化减缓.该研究可为GCL在渠道衬砌中大面积推广应用提供依据.%Geosynthentic clay liners (GCL) have great application value in canal lining projects. In order to estimate the effects of aging factors on the mechanical properties of GCL as canal lining materials, a series of laboratory simulation and field experiments in Inner Mongolian Hetao irrigation district were conducted to test effects of the five aging factors on the mechanical indexes of three kinds of GCL. The results indicated that temperature, humidity and ultraviolet radiation had some effects on the mechanical properties of GCL. The effects of high temperature on mechanical properties of GCL were more significant than those of low temperature, and the effects of high-low temperature cycling were weaker than effects of high or low temperature separately. Three kinds of mechanical properties of GCL samples was decreased by 34.27%, 35.77%, 45.02% after high temperature (60℃) aging 72 h and 19.51%, 31.49%, 18.40% after low temperature(-40℃) aging 72 h, 19.32%, 32.62% and 38.28% after high-low temperature cycling(-℃°C for 12h and 60℃ for 12h ) 10 times and 29.08%, 18.31% and 36.17% after Ultraviolet radiation 1200 h, respectively. The mechanical properties of 2 # and 3 # decreased by 12.41%, 13.08%, but 1# has no change with GCL moisture content from 50% to 100% after high temperature (60℃) aging 24 h. GCL in field aged faster in the first year, and the mechanical properties of the three samples decreased by 12.1%, 18.5% and 17.8% respectively while mechanical properties varied mitigatively after one year. This research can provide references for the application of GCL as canal lining materials.