大型节理岩坡联合支挡结构三维有限元分析

3D Finite Element Method Analysis of Jointed Rock Slope Reinforced by Multiple Structures

大型节理岩质边坡的支挡结构体系一直是设计和研究中的重要课题。本文结合湖北恩施至重庆黔江高速公路K104+960段岩质边坡防治工程,借助于商业有限元软件ABAQUS建立了多层岩质边坡在不同支护方案下包括抗滑桩、挡土墙和锚杆联合支护体系的三维模型。该计算模型着重考虑了岩质边坡的节理作用,以强度折减法计算边坡的安全系数。研究结果揭示了抗滑桩、挡土墙和锚杆的相互作用对联合支护效果的影响,主要表现为锚杆作用于上坡,抗滑桩则主要作用于下坡,中间部分的挡土墙可以同时分担锚杆与抗滑桩的土压力。其次,通过研究抗滑桩的桩位、桩间距及桩截面对边坡稳定系数与桩身内力的影响,发现桩位在边坡中前部,桩间距在2.5~4倍桩径范围内,桩截面在1.4 m×2.1 m或1.6 m×2.4 m范围的抗滑桩为最优支护方案。

Reinforced structures for large-scale jointed rock slopeshave become an important issue in the engineering design and research. This paper aimed to optimize the measurement for a complex landslide after analysis about a cutting slope as K104＋946 in the Highway range from Enshi, I-Iubei to Qianjiang and Chongqing, including anti-sliding piles, retaining wall and anchoring. Firstly, numerical simulation models were constructed using a commercial software as ABAQUS in different cases. In these models, stability factors were calculated using the strength reduction method, which paid much attention to the slope joints. The interaction between anti-slide piles, retaining wall and anchor-bars were then discussed. It was found that the upper slope and lower slope is mainly supported by the anchor-bar and the anti-slide pile, respectively. The retaining wall can slightly bear the soil pressure from the anchor-bar and anti-slide piles. Furthermore, the relationship between stability factors and pile location, spacing and diameters were analyzed by numerical simulations. The simulation results show that the optimized support case is that piles are better to be located in front of the slope, pile spacing is about 2.5 to 4 times of the pile diameter. For the pile diameter optimization, the value can be chosen in len^h and width as 1.4 m x 2.1 m ,~r 1 t~ mx~ 4,1