海底隧道CRD法各施工部开挖对结构内力影响

Study on influence of excavation by sections with CRD method on structural internal force in undersea tunnel

以采用多部开挖矿山法施工的厦门东通道海底隧道为研究对象,选取四部开挖CRD法断面,研究CRD1、2部和CRD1、3部两种不同的开挖顺序对结构内力的影响。用振弦式钢筋计对隧道初期支护及临时支护的钢支撑进行应力监测,换算出钢支撑实际内力。对监测数据运用有限元方法进行数值建模计算,将监测数据分析结果与数值计算结果进行比较分析。研究表明:采用CRD1、2部超前开挖时的结构内力要略大于CRD1、3部超前开挖,CRD3部的开挖对结构内力的影响较大,两种开挖顺序的安全系数都满足规范要求,所以结构是安全的。

In terms of the technology of excavation by sections adopted in Xiamen East Passage Undersea Tunnel, a cross-section excavated by four sections with CRD method is selected to study the influence on the structural internal force when advanced excavation is conducted in CRD1&2 and CRD1&3 separately.In addition,stress monitoring has been conducted on the steel brace which is used as the initial support and the temporary support of the tunnel by vibrating-wire rebar gauges,and then the real internal force of the steel brace has been worked out as well.Meanwhile,the monitored data has been calculated by numerical modeling with finite element method. With the monitored results and the calculated results having been compared and analyzed,the research shows that the structural internal force is obviously larger when advanced excavation is conducted in CRD1&2 than in CRD 1 &3 and the excavation on CRD3 has a much greater influence on the structural internal force.The safety factors of both excavation methods can satisfy the needs of the specification,so the structure turns out to be safe.