内层钢板外层高强度混凝土复合井壁受力特性与支护结构参数优化分析

Optimization analysis of the stress characteristics and supporting structure parameters of the composite shaft lining with inner steel plate and outer high-strength concrete

针对内层钢板外层高强度混凝土复合井壁的厚度设计,以受均匀围压的内层钢板外层高强度混凝土复合井壁得出的弹性解析解为基础,对内层钢板采用Mises屈服准则,外层高强度混凝土采用统一强度理论,研究复合井壁的初始屈服临界状态.以内层钢板和外层高强度混凝土均未屈服为条件,提出复合井壁的设计流程.结果表明,当内半径、围压以及材料给定时,存在外半径和分层半径的最佳取值范围,在此范围内选择外半径和对应的分层半径,内层钢板和外层高强度混凝土均不会达到屈服.与模型试验进行对比,发现试验中内半径、外半径、分层半径和材料给定的复合井壁,当围压等于设计围压时,外半径和分层半径处于最佳取值范围;当围压继续增大时,外层高强度混凝土先于内层钢板屈服.弹性解与屈服准则相结合,得到复合井壁设计流程为:通过规范及工程地质条件确定井壁内半径和围压值,选定复合井壁的材料,采用屈服准则求得外半径和分层半径的最佳取值范围.

Based on the elastic analytical solution of the composite shaft lining with inner steel plate and outer high-strength concrete subjected to uniform confining pressure,the Mises yield criteria and unified strength theory were used to design the thicknesses of the inner steel plate and the outer high-strength concrete,respectively,and the initial yield state of the composite shaft lining was studied.In terms of the condition that the inner steel plate and the outer concrete be not yielded,the design scheme of the composite shaft lining was proposed.The results showed that when the inner radius,confining pressure and materials were given,there existed an optimal range of the outer and delamination radii.If the outer radius and the corresponding delamination radius were selected in this range,the inner steel plate and the outer high-strength concrete would not be yielded.Compared with a model test,it was found that for the tested composite shaft lining with given inner,outer,delamination radii and materials,when the con-fining pressure was chosen to be equal to the proposed design value,the outer and delamination radii would be in the optimal range.The model test also showed that,when the confining pressure continued to increase,the outer high-strength concrete entered plasticity before the inner steel plate.Combining the elastic solution and the yield criterion,the design process of the composite shaft lining can be given as follows:the inner radius and the confining pressure value of the shaft lining are first determined by the specification and engineering geological condition,and second,the materials of the composite shaft lining are selected,and the yield criteria are used to obtain the optimal range of the outer radius and the delamination radius.