Semi-Empirical Method for Excavation-Induced Surface Displacements—Los Angeles Metro K Line Crenshaw/LAX Transit Project
Semi-Empirical Method for Excavation-Induced Surface Displacements—Los Angeles Metro K Line Crenshaw/LAX Transit Project
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开挖引起的表面位移的半经验方法 - 洛杉矶地铁 K 线克伦肖/洛杉矶国际机场交通项目
DOI：
10.1061/9780784484708.046
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发表时间：
2023
期刊：
影响因子：
--
通讯作者：
Lemnitzer, Anne
中科院分区：
文献类型：
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作者：
Beaino, Charbel;Hashash, Youssef M.;Bernard, Timothy;Hutter, Abby;Jasiak, Maksymilian;Lawrence, Jack;Szewczyk, Alicia;Zhao, Wendi;Pearce, Michael;Lemnitzer, Anne
为了评估潜在的结构破坏，需要估计城市地区开挖引起的地表位移。经验沉降分布模型已被广泛应用于估算深基坑围护结构的影响范围和地基响应。作为洛杉矶地铁K线克伦肖/LAX交通项目的一部分，三个地下车站的挖掘提供了一个独特的机会来收集现场测量数据，以改善对地面变形的估计。其中一个开挖采用了跨地段支撑、士兵桩和木板，而另外两个则由跨地段支撑和更坚固的土工搅拌墙(CSM)支撑。对于刚性支撑系统和相对较小的墙体移动的开挖，地表上移或隆起控制地表响应，而较灵活的墙体体系在开挖时测量地表沉降。这种隆起行为往往被相对较大的墙体移动引起的沉降所掩盖，因此通常被忽视。通过将开挖卸荷理想化为地表向上的条形荷载，弹性向上移动的Boussinesq解可以与侧向墙体移动引起的沉降分量相结合来估计开挖引起的地表位移的大小和分布。
Estimating excavation-induced ground surface displacements in urban areas is needed to assess potential structure damage. Empirical settlement distribution models have been widely used to estimate the zone of influence and ground response behind braced excavation walls. Three underground station excavations, part of the Los Angeles Metro’s K Line Crenshaw/LAX Transit Project, offer a unique opportunity to collect field instrumentation data to improve estimates of ground deformations. One excavation employed cross-lot braces and soldier piles and wood lagging while the other two were supported by cross-lot braces and stiffer Cutter-Soil-Mixing (CSM) walls. For the excavations with stiff support systems and relatively small wall movements, upward surface displacement or heave governed the ground surface response, while surface settlement was measured at the excavation with the more flexible wall system. This heave behavior is often masked by settlement caused by relatively large wall movements, and is thus commonly disregarded. By idealizing the excavation unloading as an upward strip load at the ground surface, the Boussinesq solution for elastic upward movement can be used in combination with a settlement component resulting from lateral wall movements to estimate the magnitude and distribution of excavation-induced surface displacements.