浅埋隧道施工中管线渗漏水对地层变形和破坏的影响

发布时间：2018-04-26 10:01

本文选题：管线渗漏 + 浅埋隧道　；参考：《北京交通大学》2014年硕士论文

【摘要】：摘要：近年来城市浅埋隧道施工中管线渗漏水诱发的地面塌陷事故频繁出现,针对这一现状,本文采用室内模型试验、颗粒离散元(PFC2D)数值模拟和理论分析相结合的研究方法,基于常见城市地区的软弱围岩,对浅埋隧道施工中管线渗漏水对地层变形和破坏的影响进行了系统研究,取得的主要研究成果如下： (1)无管线渗漏时,隧道开挖之前,地层处于稳定状态,开挖以后,隧道上覆地层逐渐坍塌至地表；有管线渗漏时,隧道开挖之前,管线渗漏水的存在导致地表出现明显沉降,开挖以后,渗漏水弱化了地层成拱效应,隧道上覆地层不但发生了整体坍塌破坏,且破坏范围较无管线渗漏时要大。 (2)管线渗漏情况下,随着渗漏水范围的增大,隧道开挖前由渗漏水引起的地表沉降增大,隧道开挖后地层失稳破坏范围和破坏速率增大,因此渗漏水的增多加剧了开挖面上覆地层变形,加速了地层坍塌破坏。 (3)管线位置的偏移导致管线渗漏水范围向同一侧偏移,隧道开挖前渗漏水引起的地表沉降范围及开挖后地层塌方破坏范围也随之向同一侧偏移；管线位置的下移使得管线距隧道拱顶的距离减小,渗漏水范围减小,上覆地层变形减弱,最终地层失稳破坏范围减小。 (4)随着管线内水压力的增大,管线渗漏水范围及隧道开挖前由渗漏水引起的地表沉降随之增大,隧道开挖后开挖面上覆土层变形及最终地层失稳破坏范围也相应的增大。
[Abstract]:Abstract: in recent years, ground collapse accidents induced by pipeline leakage occurred frequently in urban shallow tunnel construction. In view of this situation, this paper adopts the method of combining numerical simulation and theoretical analysis of indoor model test, particle discrete element PFC2D). Based on the soft surrounding rock in common urban areas, the influence of pipeline leakage on formation deformation and damage in shallow tunnel construction is studied systematically. The main research results are as follows: 1) when there is no pipeline leakage, the stratum is in a stable state before the tunnel is excavated. After excavation, the overlying stratum of the tunnel gradually collapses to the surface. When there is a pipeline leakage, the existence of the pipeline leakage water before the tunnel excavation results in the obvious settlement of the surface. After excavation, leakage water weakens the formation arch effect, and the overlying strata of the tunnel not only collapse and destroy, but also the damage range is larger than that without pipeline leakage. (2) in the case of pipeline leakage, with the increase of leakage range, the ground subsidence caused by leakage water increases before tunnel excavation, and the failure range and failure rate of stratum instability increase after tunnel excavation. Therefore, the increase of water leakage intensifies the deformation of the overlying stratum on the excavating surface and accelerates the collapse and destruction of the stratum. (3) the migration of pipeline position causes the leakage range of pipeline to the same side, and the ground subsidence range caused by leakage water before tunnel excavation and the damage range of stratum collapse after excavation are also shifted to the same side. The downward shift of the pipeline position reduces the distance between the pipeline and the vault of the tunnel, decreases the scope of leakage, weakens the deformation of the overlying strata, and reduces the ultimate range of instability and failure of the formation. 4) with the increase of the water pressure in the pipeline, the leakage range of the pipeline and the surface settlement caused by the leakage water before the tunnel excavation will increase, and the deformation of the overlying soil layer on the excavated surface of the tunnel and the failure range of the ultimate formation instability will also increase correspondingly after the excavation of the tunnel.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U455.49

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