小直径盾构隧道管片抗弯承载试验研究

220 k V犀牛站118 m转弯半径电缆隧道在国内首次采用外径4.1 m、内径3.6 m、宽0.8 m的小直径钢筋混凝土盾构管片。为研究该管片的抗弯性能以及盾构手孔对刚度的影响,对其进行试验研究,量测试验构件的挠度与裂缝宽度;采用ABAQUS有限元软件建立三维模型模拟管片加载全过程;同时采用《混凝土结构设计规范》(2002版与2010版)计算管片在不同荷载工况下的裂缝宽度,并与实测值进行比较。研究结果表明:小直径盾构管片发生典型的弯曲破坏,构件延性良好;裂缝宽度实则值与2010版《混凝土结构设计规范》计算结果吻合良好;盾构手孔对管片的刚度影响较小。

Experimental Study on Bending Performance of Small-diameter Shield Tunnel Segments

It is the first time in China that small diameter concrete segments (with the outer diameter being 4.1 m, the inner diameter being 3.6 m and the width being 0.8 m) have been used for the 220 kV cable tunnel from Xiniu substation to Qilin substation in Guangzhou, which has a 118 m turning radius section. In the paper, the bending capacity of the segments and the influence of the handhole on the stiffness of the segments are tested, and the deflection and crack width of the structure are measured. The loading process is simulated by means of 3D model using ABAQUS finite element software. The crack width is calculated by using methods specified in Code for Design of Concrete Structures (GB 50010-2002 and GB 50010-2010) and the calculation result is compared to the measured results. The study results show that: Bending failure occurs to small diameter shield tunnel segments, and the ductility of the segment is good; The measured crack width agrees well with results calculated according to Code for Design of Concrete Structures (GB 50010-2010); The influence of the handhole on the stiffness of the segments can be ignored.