掏挖与岩石锚杆复合型基础上拔承载机理和影响因素研究

针对掏挖与岩石锚杆复合型基础上拔承载机理不明确的问题,基于现场试验工况,利用Plaxis3D有限元软件建立复合型基础抗拔承载模型,研究其上拔承载机理。在此基础上,研究了土体弹性模量、岩体弹性模量、土体黏聚力对复合型基础各部分的承载影响,分析了掏挖基础和岩石群锚基础的承载力发挥情况、上拔变形、塑性区开展,并给出了复合型基础的改进方案。结果表明:上拔变形刚度较大的岩锚基础对复合型基础的承载极限状态起控制作用;掏挖基础和岩石锚杆基础的上拔变形协调性是影响复合型基础承载力发挥的关键;适当增加掏挖基础嵌入岩石的深度可有效提高复合型基础的抗拔承载力。

Uplift Bearing Mechanism and Parameter Influence of Excavation and Rock Bolt Composite Foundation

The bearing mechanism of the composite foundation of excavation and rock bolt was unclear. In view of this, an analytical model of the uplift bearing capacity of the composite foundation was established using Plaxis3D based on field test conditions to probe into the uplift bearing mechanism of the composite foundation foundation. The influences of soil elastic modulus, rock elastic modulus, and soil cohesion on the bearing capacity of each part of the composite foundation were examined. The bearing capacity, uplift deformation, and plastic zone development of excavation foundation and rock bolt were analyzed. The improved design of the composite foundation was also given. Results demonstrate that the rock bolt with large deformation stiffness controls the ultimate state of uplift bearing of the composite foundation; the deformation compatibility between excavation foundation and rock bolt is the key to the bearing capacity of the composite foundation. Increasing the depth of the excavation foundation embedded in rock can effectively improve the pull-out bearing capacity of the composite foundation.