干湿循环作用下红黏土裂隙发育试验研究

Experimental Study on Fracture Development of Red Clay under Wetting and Drying Cycles

对江西红黏土路基填料进行干湿循环试验,比较不同压实度的红黏土试样在干湿循环作用下的裂隙发育情况。试验所用红黏土在最优含水率附近力学性质较好,即使压实度降低到87%,依然能满足抗剪强度和压缩性要求。同时考虑规范对于最低压实度的要求,对压实度为90%和93%的试样进行干湿循环试验。结果表明:在经过6次干湿循环作用后,90%和93%的试样均产生明显的裂隙;93%压实度的土样,相比90%压实度的土样,裂隙发育宽度更细,网状裂隙包裹的土块面积大,边缘土体跌落少,完整性更好;但提高压实度不能防止裂隙的发育,只能抑制裂隙的进一步发育。试验结果可为研究红黏土作为路基填料在干湿循环作用下的路用性能提供依据。

The dry-wet cycle tests of Jiangxi red clay roadbed fillers were carried out to compare the fracture development of red clay samples with different compactness under the dry-wet cycle.The red clay used in the test is near the optimal water content and has good mechanical properties.Even if the compactness is reduced to 87%,it can still meet the requirements of shear strength and compressibility.At the same time,the requirements of the specification for the lowest pressure compactness are considered,so the test samples with compactness of 90%and 93%are dry-wet fracture tests.The results show that after 6 cycles of wetting and drying,90%and 93%of the samples have obvious cracks.Compared with 90%compactness soil sample,93%compactness soil sample has finer fissure width,larger area of soil block wrapped by network fissure,less soil drop at the edge,and better integrity.However,increasing the degree of compaction can not prevent the development of cracks,but can inhibit the further development of cracks.The experimental results can provide experimental basis for studying the performance of red clay as roadbed filler under wetting and drying cycles.