深埋双圆盾构隧道的横向地震响应特性研究

阐述反应位移法的基本原理和深埋双圆盾构隧道的地层荷载模式,并基于反应位移法和梁弹簧模型,对双圆盾构隧道仅受静载和静载与水平剪切地震荷载同时作用下结构的变形和内力等动力响应特性进行研究。分析表明:与对称静载作用下相比,在静载与地震荷载同时作用时,结构的变形和内力不再是对称的;弯矩和变形走势基本一致,两洞各自上半圆的迎地层位移侧和下半圆的背地层位移的衬砌基本都有向洞内的位移和内侧受拉的弯矩,两洞各自上半圆的迎地层位移侧和下半圆的背地层位移的衬砌基本都具有相反方向的位移和弯矩,与中柱底部连接处的弯矩集中现象得到消除;衬砌的轴力不再是全部为受压值,而是出现大范围受拉的情况,且拉力值较大,中柱的压力值减小十分明显;与中柱连接处的剪力集中现象消除明显,远离中柱处的管片衬砌剪力绝对值增大明显。

Study on Transverse Seismic Response of Deeply-buried Double-O-Tube Shield Tunnel

The basic principle of response displacement method and the stratum load pattern of deeplyburied double-o-tube shield tunnel were described in this study. And then, based on response displacement method and beam-spring model,the structural deformations,internal forces and other dynamical response characteristics of double-o-tube shield tunnel were studied under the action of only static load,as well as under the combined action of static load and horizontal shear seismic load. The study shows that:( a) Compared with those under the action of symmetrical static loads,the structural deformations and internal forces under the combined action of static load plus seismic load are no longer symmetrical.( b) The bending moment trend is basically the same as the deformation trend. For both the two tubes,at the lining of upper half of the circle in face of the stratum displacement,and at the lining of lower half of the circle not in face of the stratum displacement,there are the deformations towards tube inner and the inner-side-tensioned bending moments; while at the opposite linings,the directions of deformations and bending moments are basically opposite to the above-mentioned. The phenomenon of bending moment concentration is eliminated at the place connecting to the middle pillar bottom.( c) The axial forces of the lining are no longer all pressure forces but a wide range of tensile forces with greater amplitudes; and there is obvious reduction of pressure forces of middle pillar.( d) There is obvious elimination of the phenomenon of shear concentration at the place connecting to the middle pillar,while there is obvious increasing of shear absolute values at the segment lining away from the middle pillar.