考虑土拱效应的超大断面隧道上覆土影响因素分析

Analysis on Influence Factor of Overlying Soil of Super Large Section Tunnel Considering Soil Arching Effect

超大断面隧道上覆荷载是隧道支护结构设计的关键参数。依托某超大断面隧道工程,建立数值模型分析不同覆土厚度与洞径之比下土层黏聚力、内摩擦角和剪胀角对隧道上覆土竖向应力的影响。结果表明:随着覆土厚度与洞径之比增加,土拱效应逐渐显现;各地层参数对隧道上覆土竖向应力的影响程度由大到小依次为内摩擦角、黏聚力、剪胀角。

The overlying soil load in super large section tunnel has important reference significance for the design of tunnel supporting structure.Based on a super large section tunnel,a numerical tunnel model was established to analyze the influences to vertical overlying soil stress above the center of the arch in different cohesion(c),internal friction angle(φ)and dilatancy angle(ψ)under the ratios of soil cover thickness(H)to tunnel diameter(D).The results show that,with the increase of the ratios of H to D,the soil arching effect gradually appears.The influence degree of the formation parameters on the vertical overlying soil stress isφ>c>ψ.