循环荷载下台阶式加筋土挡墙力学与变形性能的试验研究

Experimental study on mechanical and deformation performances of geogrids-reinforced soil retaining walls under cyclic loading

台阶宽度是影响台阶式加筋土挡墙力学与变形性能的重要因素之一。首先开展室内单级加筋土挡墙极限承载力试验,基于此确定循环荷载幅值,进而研究循环荷载作用下台阶宽度D对二级台阶式加筋土挡墙位移、土压力、筋材应变规律和可能的潜在滑动面影响。试验结果表明:面板位移最大值及附加水平土压力峰值出现在墙高约0.85H(H为总墙高)处;台阶越宽,下级墙面板位移、附加水平压力和墙底靠近面板处垂直压力减小,底层筋材应变也呈减少趋势;承载板基础沉降和挡墙面板水平位移在试验初期加载时增加明显,当循环次数N大于5000次后增幅减缓并呈收敛趋势;上级挡墙可能的潜在滑动面以贯穿加载板近面板端和0.6H1(H1为上级墙高)面板处或者贯穿加载板远面板端和(0.3~0.4)H1面板处为主。该成果将丰富试验研究并为实践应用提供借鉴和参考。

Offset distance is one of the key factors affecting the mechanical and deformation performances of multi-tiered geogrids-reinforced soil retaining walls(GRSRW). Firstly,the ultimate bearing capacity test of the single-tiered GRSRW was carried out in door to determine the magnitude of the cyclic load. Furthermore,the displacement,the earth pressure and the reinforcement strain in multi-tiered geogrids-reinforced soil retaining walls(MGRSRW) and potential sliding surface were analyzed under consideration of variation of the offset distance D. The test results show that the maximum displacement of the panel and the peak of the additional horizontal earth pressure appear at 0.85 height of the wall. With increasing the offset distance,the horizontal displacement and the additional horizontal earth pressure of the lower retaining wall as well as the additional vertical pressure near the bottom of the panel decrease,and the strain of the geogrid at the bottom also decreases. The foundation settlement and the horizontal displacement of the retaining wall face increase obviously at the beginning of the test,while the increase amplitude slows down and converges as the number of cycles N is greater than 5 000. The potential sliding surfaces of the upper retaining wall mainly pass through the side of the loading plate near the facing panels and 0.6 height of the upper wall,or through the side of the loading plate away from the facing panels and 0.3–0.4 height of the facing panel. The results will enrich experimental researches and provide reference for practical applications.