内水压作用下盾构隧道自由变形法力法推导和力学特性研究

Force Method Derivation and Mechanical Characteristics of Shield Tunnels by Free-form Deformation Method Under Inner Water Pressure

基于自由变形法理论对内水压作用下的盾构隧道结构内力进行了力法推导,并将计算结果与整环足尺加载试验数据进行了对比验证,进一步研究了不同埋深以及不同内水压作用下隧道结构的力学特性。研究结果表明:非满管状态下隧道结构的弯矩随着内水压力的增加而增大,轴力略微减小;满管状态下,随着内水压力的增大,隧道结构弯矩基本保持不变,轴力大幅度减小;偏心距随着埋深的减小而大幅度增大,结构受力状态从压弯逐渐过渡为拉弯,对结构的承载以及裂缝控制极为不利,设计时要预留足够的安全储备。相关结论为类似工程计算提供了参考,具有一定的工程实用性。

Under different inner water pressure,the tunnel structures internal forces are calculated by force method deduction based on the theory of free-form deformation method.The calculated results are compared with the measured data of the full-scale loading test of the tunnel structures.Furthermore,the mechanical characteristics of tunnel structure are studied under different burial depths and different internal water pressures.The research results indicate that the bending moment of tunnel structure increases with the increase of internal water pressure and the axial force decreases slightly under the condition of non-full pipe state;Under the full pipe state,when the inner water pressure continues to increase,the structural bending moment remains basically unchanged,the axial force decreases greatly;And with the buried depth decreases,the eccentricity increases greatly.The stress state of the structure gradually changes from compression bending to tension bending,which is extremely unfavorable to the load bearing and crack control of the structure.Sufficient security reserve should be considered during design.The conclusions have certain engineering practicability because it can provide reference for the calculation of similar engineering design.