基于收敛-约束法地铁区间隧道初期支护安全性研究

发布时间：2019-03-20 17:14

【摘要】：本文以西安地铁区间隧道为工程背景,采用理论分析、数值模拟与现场试验等研究手段,基于收敛-约束法原理对现行支护参数安全性进行评价,得到结论如下:黄土地层特征曲线可分为直线与曲线段,洞周边墙地层首先发生屈服,并逐渐形成塑性滑移楔体向拱顶和拱底蔓延;复合式支护结构中各构件以并联方式共同承担地层压力;支护结构进入塑性状态后其力学性能急剧恶化,由于施工与运营不允许支护结构出现塑性屈服,本文从容许位移的角度提出定义支护结构安全系数的方法;现场试验中支护结构能提供的最大支护反力大于围岩与支护特征曲线平衡点应力,表明现行支护参数满足安全性要求;从容许位移角度提出支护结构安全性评价方法,通过有限元计算结果绘制相关部分的地层与支护特征曲线可得对应安全系数,计算表明隧道支护结构安全系数最小为边墙处1.14,设计与施工中应予关注。
[Abstract]:Based on the theory analysis, numerical simulation and on-site test, the safety of the existing supporting parameters is evaluated based on the convergence-constraint method, and the conclusion is as follows: the loess formation characteristic curve can be divided into straight line and curve section. in that composite support structure, the formation pressure is jointly bear by the components in the composite support structure, and the mechanical property of the support structure is rapidly deteriorate after the support structure enters the plastic state, Because the construction and operation do not allow the plastic yielding of the supporting structure, the method of defining the safety factor of the supporting structure is proposed from the allowable displacement angle; the maximum supporting reaction force provided by the supporting structure in the field test is larger than the stress of the balance point of the surrounding rock and the supporting characteristic curve, The method for evaluating the safety of the supporting structure is presented from the allowable displacement angle, and a corresponding safety factor can be obtained by using the finite element calculation result to draw the formation and the supporting characteristic curve of the relevant part, The calculation shows that the minimum safety factor of the tunnel support structure is 1.14 at the side wall, and the design and construction should be paid attention to.
【作者单位】：北京城建设计发展集团股份有限公司;
【分类号】：U231.3;U455.7

【共引文献】