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桩锚支护是边坡加固的主要措施之一,从桩间土拱形成机理和土拱轴线形态出发,建立了土拱横截面抗剪切效应下土拱等效简支梁的挠度计算式,诠释了桩间土拱凸向桩后土体的特点。同时考虑了土体粘结力、内摩擦角和锚索拉力水平向分量及其时变特性对桩间土体应力状态的影响,并结合桩间土拱横截面Coulomb剪切准则和土拱横截面静力平衡条件,分别推导了正常土体、抗剪土体、土体蠕变属性和土体蠕变桩锚耦合作用等4种情况的拱轴线方程。比较分析了上述4种情况两相邻桩的最大跨度。结果表明第2种情况两相邻桩的最大跨度值为最大,其次是第4种情况和第3种情况,而第1种情况的跨度值为最小。研究结果验证了理论推导式的有效性,建议抗滑桩加固边坡设计中应以第4种情况进行桩中心距取值。所述结论可为了解桩间土拱蠕变弱化机理、拱轴线时变特征和桩锚工程设计参数取值提供有益参考。
Pile-anchor supporting is one of the main measures for slope reinforcement. Based on the formation mechanism of soil arching between piles and the shape of soil arch axis, the formula for calculating the deflection of soil-arch equivalent simply-supported beam under cross-shear shear resistance is established , The interpretation of the soil between the piles of soil arching convex piles characteristics. At the same time, the influence of the horizontal component of the soil adhesion force, internal friction angle and tension of horizontal cable and its time-varying characteristic on the stress state of the soil between the piles is considered. Combined with the Coulomb shear criterion of cross-section between the soil and arch, The equations of the arch axis of four kinds of conditions, normal soil, shear strength, soil creep property and soil-creep pile-anchor coupling effect are derived respectively. The maximum span of two adjacent piles in the above 4 cases is comparatively analyzed. The results show that in the second case, the maximum span value of two adjacent piles is the largest, followed by the fourth case and the third case, while the first case has the smallest span value. The research results verify the validity of the theoretical derivation. It is suggested that the pile center distance should be taken as the fourth case in the anti-slide piles reinforcement slope design. The conclusion can provide a useful reference for understanding the mechanism of soil arching creep and weakening, the time-varying characteristics of arch axis and the design parameters of pile-anchor engineering.