基于有条件联合承载机理的导流隧洞衬砌安全与加固措施研究

Study on lining safety and strengthening measures for diversion tunnel based on conditional combined load-bearing mechanism

针对高边墙的导流隧洞,结合某导流洞工程实例,建立了包含衬砌、围岩和支护结构在内的数值分析模型,采用有限抗拉强度材料反映衬砌与围岩间粘结强度有限的受力特征,分析了封堵期间在外水压力作用下衬砌与围岩的有条件联合承载特性,进而校核了衬砌结构的安全性。结果表明:随着衬砌与围岩粘结强度的降低,衬砌应力数值随之增加,所需最小抗剪厚度也越来越大;当衬砌厚度不满足条件时,可将衬砌内钢筋与外围锚杆绑扎或在衬砌内表面施加锚筋桩加固;相比钢筋与外围锚杆绑扎的加固措施,锚筋桩加固措施更为有效。

Aiming at the diversion tunnel with high side-wall, a numerical analysis model consisted of lining, surrounding rock and supporting structures is established herein in combination with an actual engineering case of a diversion tunnel, and the con- ditional combined load-bearing characteristics of the lining and the surrounding rock under the external water pressure during the plugged period of the tunnel are analyzed by reflecting the limited stress characteristics of the bonding strength between the lining and the surrounding rock with the material of limited tensile strength, furthermore, the safety of the lining structure is checked as well. The result shows that not only the stress value of the lining is to be increased, but the necessary minimum anti-shearing thickness of the lining is also to be larger and larger along with the decrease of the bonding strength between lining and surround- ing rock. When the lining thickness cannot satisfy the safety conditions, the reinforcement inside of the lining can be assembled together with the outside anchor-bolts or strengthening the inner surface of the lining with anchoring piles. Compared with the for- mer strengthening measure mentioned above, the latter one is more effective.