不同形式单侧壁扩建下在建隧道受荷差异性研究

Study on Load Difference of Tunnel Under Construction with Different Forms of Single Sidewall Expansion

不同形式的扩建方式是影响隧道施工经济安全的关键技术问题,为研究不同形式下单侧壁扩建方式对在建隧道围岩受载特征的影响,通过结合实测数据与数值模拟相结合的手段,揭示了在建隧道全状态下围岩体结构的形变特征规律,并定量刻画了不同方式、不同距离下在建隧道开挖支护形式的力学特征,探明确定最优的施工方案。研究结果表明:(1)在建隧道扩建区段内,围岩体产生的变形偏压量数值上整体增幅85%左右,拟建区段内,水平位移增幅较竖向位移增幅大20%左右;(2)基于单侧壁台阶法开挖形式,循环距离每增加0.5 m,围岩体结构变形增幅在5%~20%左右;(3)开挖循环间距为4 m时是单侧壁全断面开挖法的最优施工距离。

Different forms of expansion methods are the key technical problems affecting the economic safety of tunnel construction.In order to study the influence of different forms of single sidewall expansion methods on the loading characteristics of surrounding rock of tunnel under construction,the deformation characteristics of surrounding rock structure under the whole state of tunnel under construction are revealed by combining measured data with numerical simulation,and different methods are described quantitatively According to the mechanical characteristics of excavation and support forms of tunnels under construction at different distances,the optimal construction scheme is determined.The results show that:(1) in the expansion section of the tunnel under construction,the deformation bias pressure generated by the surrounding rock increases by about 85% as a whole,and in the proposed section,the increase of horizontal displacement is about 20% greater than that of vertical displacement;(2) based on the excavation form of single side wall bench method,the structural deformation of the surrounding rock increases by about 5% ~ 20% every 0.5 m increase in the circulating distance;(3) When the excavation cycle spacing is 4 m,it is the optimal construction distance of single side wall full section excavation method.