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盾构隧道在运营过程中会出现局部渗漏水,对结构的长期安全性有较大影响。目前渗漏水研究中,难以对局部渗漏及盾构隧道的力学特性同时进行准确的模拟。针对该现状,提出一种组合模拟方法,即渗流计算时,管片结构采用均质圆环模型,在局部接头处设置相应的渗流路径;而在力学计算时,关闭渗流场,将管片结构的均质圆环模型替换为考虑接头抗弯刚度非线性的壳–弹簧–接触–地层模型,迭代计算达到平衡。采用该方法对不同渗流量及渗漏位置情况下,隧道周围孔隙水压力分布规律及结构的力学行为进行了对比分析。分析结果表明:渗漏量越大,孔隙水压力降低越明显,结构内力变化越显著,且拱腰附近接头渗水对结构内力的影响程度大于拱顶与拱底附近接头渗水;各接头渗水时,影响区域的划分表现出一致性,即以渗水接头为中心,两侧各36°的区域为严重影响区域;与严重影响区域相连,两侧各48°,60°区域为一般影响区域,剩余区域为微弱影响区域。复合地层情况下,与静水压力工况相比,上半部分渗水导致结构上侧正弯区域增加,下半部分渗水导致结构下侧正弯区域增加,且轴力沿全环分布不均,渗漏侧轴力平均值小于非渗漏侧轴力,对管片结构受力不利。
Shield tunnel in the operation process will be partial leakage of water, the long-term structural safety has a greater impact. In the current study of seepage water, it is difficult to accurately simulate the local leakage and the mechanical properties of the shield tunnel at the same time. Aiming at the current situation, a new method of combination simulation is proposed, that is, when the seepage calculation is carried out, the homogeneous ring model is adopted in the pipe structure and the corresponding seepage flow path is set at the local joint. In the mechanical calculation, the seepage field is closed, Homogeneous ring model is replaced by a shell-spring-contact-formation model considering the non-linear bending stiffness of the joint, and the iterative calculation is balanced. By using this method, the pore water pressure distribution around the tunnel and the mechanical behavior under different seepage and seepage locations are compared and analyzed. The results show that the greater the leakage is, the more obvious the pore water pressure decreases, and the more obvious the internal force changes. The influence of seepage around the arch waist on the structural internal force is greater than that of the joints near the arch and the arch. The division of the affected area shows consistency, that is, the area with 36 ° on both sides is the serious affected area with the water-permeable joint as the center; the area with 48 ° and 60 ° on both sides is the common influence area, and the remaining area For weak influence area. In the case of composite strata, seepage of the upper half of the structure leads to an increase in the upper-right bend area of the structure and seepage of the lower half of the structure results in an increase in the positive-bend area of the lower side of the structure, and uneven distribution of axial forces along the entire ring, as compared with the case of hydrostatic pressure The average value of leakage axial force is less than the non-leakage side axial force, the negative pressure on the structure of the segment.