Model Tests for Two-Tier Slopes Supported with Ridge Walls of Geotextile Bags Under Lateral Loading
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摘要: 为研究二级边坡织物袋坎墙侧向承载特性,开展了4种织物袋坎墙支护(无支护、单坎型支护、L坎型支护及反坡L坎型支护)和3种坡比(1∶0.3、1∶0.5及1∶0.75)状态下二级边坡侧向非均匀加载模型试验,分析侧向加载作用下坡体位移和墙后土压力的变化。结果表明:在侧推位移作用下,各个试验中第二级边坡水平位移均大于第一级边坡,同时第二、一级边坡墙后土压力均随墙高呈增大趋势,且第一、二级边坡连接处土压力最大;以无支护边坡作为参照,单坎型、L坎型及反坡L坎型支护的第二级边坡坡顶水平位移分别减小了8.6%、13.2%和16.5%,且单坎型支护的第二级边坡坡脚处土压力增大了19.3%,L坎型支护的第二级边坡坡脚处土压力增大了32.6%,反坡L坎型支护的第二级边坡坡脚处土压力增大了42.2%,以坡比为1∶0.3的单坎型支护边坡作为参照,坡比为1∶0.5的第二级边坡坡顶拱起高度增加了18.2%、坡顶水平位移减小了7.1%、坡脚土压力增加了7.8%,坡比为1∶0.75的第二级边坡坡顶隆起高度增加了34.8%、坡顶水平位移减小了10.9%、坡脚土压力增加了23.1%。表明第二级边坡均先于第一级边坡发生破坏,且反坡L坎型织物袋坎墙支护下第二级边坡抵抗侧向变形能力最大,同时坡比越小,边坡抵抗侧向变形能力越大,柔性坎墙抵抗侧向土压力能力越大,承载能力越高。Abstract: To explore the lateral bearing characteristics of two-tier slopes supported with ridge walls of geotextile bags, the model tests of two-tier slopes under non-uniform lateral loading were conducted in the conditions of four kinds of ridge walls supported with geotextile bags, including no support, inclined type supporting, L-shaped supporting and L-shaped supporting with notched sills, and three kinds of slope rates involving 1∶0.3, 1∶0.5 and 1∶0.75, respectively. The displacement of the slopes and earth pressure were analyzed under lateral loading. The results showed that the horizontal displacement of the second tier slopes was greater than those of the first tier slopes. Simultaneously, the earth pressure behind those walls increased with the wall height. And the earth pressure at the connections between the first and second tier slopes was the largest. Taking the non-supporting slope as reference, the horizontal displacement at the tops of the second tier slopes with inclined type, L-shaped and L-shaped supporting with notched sills decreased by 8.6%, 13.2% and 16.5%, respectively, and the earth pressure at the toes of slopes with inclined type supporting increased by 19.3%, and the earth pressure at the toes of the second tier slopes with L-shaped supporting increased by 32.6%. The earth pressure at the toes of the second tier slopes with L-shaped supporting with notched sills increased by 42.2%. Taking the slope at a slope rate of 1∶0.3 as reference, the heave height on crests of the second tier slopes at a slope rate of 1∶0.5 increased by 18.2%, the horizontal displacement of slope tops decreased by 7.1%, and the earth pressure at toes of slope increased by 7.8%. Simultaneously, the heave height on crests of the second tier slopes at a slope rate of 1∶0.75 increased by 34.8%, the horizontal displacement of slope tops decreased by 10.9%, the earth pressure at the toes of slopes increased by 23.1%. It showed that the failure of the second tier slopes preceded that of the first tier slopes. The lateral deformation resistance of the second tier slopes was maximum in support of geotextile-bag ridge walls with the L-shaped supporting with notch sills. In addition, the smaller the slope ratio was, the greater the capacity of the slope to resist lateral deformation was, the greater the capacity of the flexible ridge wall to resist lateral earth pressure was, and the larger the bearing capacity was.
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Key words:
- two-stage slope /
- geotextile bag /
- lateral loading /
- lateral deformation
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