直接弹性抗力法及其在隧道初期支护结构计算中的应用  

Direct Elastic Resistance Method and Its Application to Calculation of Primary Support Structure of Tunnel

作　　者：剧仲林 JU Zhonglin(The 4th Engineering Co.,Ltd.of China Railway 12th Bureau Group,Xi′an 710021,Shaanxi,China)

机构地区：[1]中铁十二局集团第四工程有限公司,陕西西安710021

出　　处：《隧道建设（中英文）》2021年第3期372-387,共16页Tunnel Construction

摘　　要：为更加直观地证明隧道初期支护具有单独承载能力的事实,提出直接弹性抗力法原理。直接弹性抗力法以拱(圆曲梁)和弹性地基拱(弹性地基圆曲梁)2段函数分别反映拱部支护结构脱离围岩以及侧壁支护结构压向围岩2段结构的内力及位移,能极大地简化计算过程,较为真实地反映隧道支护结构的应力状态;并结合链杆支座拱、铰支座拱模型,分别模拟实际施工的无分布锚杆影响、有分布锚杆影响但锚杆无切向力、有分布锚杆影响且锚杆有切向力3种支护应力状态,比较全面地概括隧道支护施工可能产生的应力状态,充分证明隧道初期支护具有单独承载能力的理论事实。强调“先柔后刚,先放后抗”属于概念,初期支护变形的主要原因是地基承载力不足造成沉降,锚杆锚固力和喷射混凝土早期强度等严重影响初期支护单独承载;再根据隧道支护结构各种可能的应力状态,提出对隧道初期支护结构细节设计的改进建议,如锚杆与钢架的连接、钢架之间的连接、钢架底脚的处理、锁脚管桩、型钢钢架与格栅钢架的组合结构等,通过实践证明隧道初期支护具有单独承载能力的理论。To prove more intuitively the fact that the primary support of tunnel has independent bearing capacity,the principle of direct elastic resistance method is put forward.In the direct elastic resistance method,two functions of arch(curved beam)and elastic foundation arch(curved beam on elastic foundation)are used to reflect the internal force and displacement of the support structure of arch from surrounding rock and the support structure of sidewall pressing against the two-section structure of surrounding rock,respectively,which can greatly simplify the calculation process and reflect the stress state of tunnel support structure more realistically.Combined with the chain rod support arch and hinged support arch models,three supporting stress states of actual construction,i.e.no distributed bolt influence,no tangential force with distributed bolt influence,and tangential force with distributed bolt influence,are simulated.The possible stress state of tunnel support construction is summarized comprehensively,and the theoretical fact that the primary support of tunnel has independent bearing capacity is fully proven.It is emphasized that"flexible support first and then rigid support,stress release first and then resistance"belongs to concept;the main reason for the primary support deformation is the settlement due to insufficient foundation bearing capacity,and the anchoring force of bolt and early strength of shotcrete severely affect the independent bearing capacity of the primary support.Finally,according to the various possible stress states of the tunnel support structure,the improvement suggestions on the detail design of the primary support structure of the tunnel are postulated,which include the connection between the anchor rod and steel frame,connection between steel frames,the treatment of the bottom foot of steel frames,foot-locking pipe pile,and the combined structure of the shaped-steel frame and the grid steel frame.The theory that the primary support of tunnel has independent bearing capacity is prov

关 键 词：隧道初期支护 假定抗力 直接弹性抗力 拱(圆曲梁) 弹性地基拱(弹性地基圆曲梁) 链杆支座 铰支座 

分 类 号：U45[建筑科学—桥梁与隧道工程]