5 水位对盾构隧道管片结构内力影响研究.pdfVIP

水位对盾构隧道管片结构内力影响研究 摘 要：当水位处于盾构隧道断面内时，管片侧向水平荷载分解为矩形荷载、满跨（跨高等于隧道直径）三角形荷载、 非满跨三角形荷载 3 部分，已有修正惯用法对第三部分荷载只能作近似处理，导致计算结果有误差。首先针对此荷载 做如下处理：理论推导管片在其作用下的内力弹性解和按面积等效原则将其荷载集度换算为对应满跨时荷载集度，并 用于计算水平地基反力及其作用下的管片内力；然后利用推导公式并结合已有修正惯用法针对国内 4 种典型盾构隧道， 分析了不同覆土条件下水位变化对管片内力的影响，得出其变化规律，可为盾构隧道结构设计提供借鉴。 关键词：盾构隧道；修正惯用法；水位；侧向水平荷载；管片内力 Influence of water level on internal force of segments of shield tunnels Abstract: The lateral horizontal load acting on segments might be divided into three parts as the water level was located within tunnel section: rectangular load, full-span (span height equal to tunnel diameter) triangular load and non-full-span triangular load. The existing modified methods might only deal with the third one approximately, and resulted in calculated results with errors. The non-full-span triangular load was dealt with as follows: firstly, deducing the elastic solution of internal force of the segments under the action of the load; secondly, converting the load intensity to the equivalent full-span one according to the laws of equivalent area. The equivalent intensity was used to calculate horizontal soil reaction and internal force of segment. With regard to four typical shield tunnels in China, the influence of water level variation on internal force of segment under different overburden thicknesses was studied using the deduced formula and the existing modified methods. The variation laws internal force of segment were obtained. It might be helpful to the structural design. Key words: shield tunnel; modified method; water level; lateral horizontal load; internal force 0 引 言 由于盾构工法具有安全、快速及适应性强等优点， 利水位工况，并以此进行结构设计，对确保工程安全 我国的隧道工程越来越倾向于采用盾构工法施工[1-2] 。 十分重要。 隧道正常使用阶段，水位会因人为性和自然性因素发 当水位处于隧道断面内时，管片侧向水平荷载为 生变化，进而影响管片力学状态，因此针对具体工程 非标准梯形形式，梯形荷载斜率在水位分界处发生突 分析结构受力