地下通道开挖宽度对地表沉降的影响

根据深圳某地下通道的施工实践,浅埋地下通道开挖宽度对地表累计沉降值影响很大,基于此,文章主要依据对地表沉降、拱顶下沉、支护与土体接触压力、支护内力等施工监测资料的详细分析和有限元法计算,针对CD法施工中地表沉降的主要构成因素:开挖阶段的初支整体下沉和中隔墙拆除阶段的结构变形,从初支接触压力、支护整体刚度、支护结构受力、支护整体下沉等方面分析了开挖宽度对地表沉降的影响情况。分析表明,开挖宽度是影响地表累计沉降值的主要因素之一,随着开挖宽度增加,支护与土体接触应力增大,开挖阶段支护整体下沉量和拆撑阶段中隔墙受力的变大是导致地表沉降量值迅速增加的主要原因。

The Effect of Subway Excavation Span on Ground Surface Settlement

According to the case of a subway in Shenzhen, the total ground surface settlement is distinctively affected by the excavation span of the subway. Based on the observation, by means of the analysis of the measurement data of ground surface settlement, arch deformation, earth pressure, support inner force etc, the effect of excavation span on ground surface settlement, which is caused by support subsidence in the phase of excavation and in the phase of removing of Central Diaphragm, is analyzed from the point view of earth pressure, support stiffness, support inner force, support subsidence, etc. It demonstrated that the excavation span is one of main factors that affect ground surface settlement, with the span increase, the growing of support subsidence and inner force is the main reason that caused the rapid increase of the ground surface settlement.