连续球体型锚杆群锚效应模型试验研究

    Experimental study on anchor group effect of continuous ball shaped anchors

    • 摘要: 为研究多扩体锚杆的群锚效应,以连续球型扩体锚杆为研究对象,分别开展不同间距比(S/D=2、3、4)、不同埋深(0.22、1.9、2.4m)、不同布置方式(平行布置、上下错位、成角度布置)的群锚上拔模型试验。对群锚上拔过程中承载力-位移关系曲线特征和锚周土体变形机制进行了分析,探索了不同间距、不同埋深以及不同布置方式对群锚效应的影响规律。试验结果表明:群锚的不同埋深会对锚周土体位移影响范围产生差异。浅埋情况下弹性阶段土体位移影响范围最大,随后逐渐减小,深埋情况下弹塑性阶段土体位移影响范围最大,而后增量位移分析表现出先扩展后收缩的特征。同时,调整锚杆布置方式可有效减弱群锚效应对系统承载力的影响。以埋深2.4m下S/D=4为例,错位布置可减少锚间土体承载力的横向扰动,较平行布置群锚效应系数提升5.3%,位移控制提高18.5%,兼具高承载力与位移稳定性,采用角度(10°、20°)布置时,群锚效应系数可分别提高2.94%和5.15%。

       

      Abstract: To investigate the group effect of multi-expanded body anchors, continuous spherical expanded anchors were studied through a series of pull-out model tests on anchor groups. Tests were conducted with varying spacing ratios (S/D= 2, 3, 4), different embedment depths (0.22m, 1.9m, 2.4m), and different arrangement configurations (parallel layout, staggered layout, inclined arrangement). The characteristics of the load-displacement relationship curves during pull-out and the deformation mechanisms of the surrounding soil were analyzed. The influence patterns of different spacings, embedment depths, and arrangement configurations on the group effect were explored. The test results indicate that the embedment depth of the anchor group significantly affects the extent of the soil displacement influence zone around the anchors. Under shallow embedment conditions, the soil displacement influence zone is largest during the elastic stage and gradually decreases thereafter. Under deep embedment conditions, the influence zone is largest during the elastoplastic stage, with subsequent incremental displacement analysis showing a characteristic pattern of initial expansion followed by contraction. Furthermore, adjusting the anchor arrangement configuration can effectively mitigate the negative impact of the group effect on the system's bearing capacity. Taking the case of S/D= 4 at an embedment depth of 2.4 m as an example: the staggered arrangement reduces lateral disturbance to the bearing capacity of the soil between anchors. Compared to the parallel arrangement, the group effect coefficient increased by 5.3%, and displacement control improved by 18.5%, demonstrating both high bearing capacity and displacement stability. When using inclined arrangements (10°, 20°), the group effect coefficient increased by 2.94% and 5.15%, respectively.

       

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