盾构刀盘扭矩对风化岩地基中邻近桩基的影响

Effects of Cutterhead Torque of Shield on Adjacent Pile in Decomposed Rock Foundation

基于地铁盾构施工对邻近某客运站桩基影响的问题,利用FLAC3D有限元模拟分析软件,通过八种工况对比分析了刀盘扭矩与盾构推力对风化岩地基中邻近桩基的影响。结果表明:刀盘扭矩与盾构推力对桩基的影响呈现不同的规律。刀盘扭矩对桩基的影响规律主要为:盾构刀盘扭矩的存在使得桩身主要产生沿隧道横向的附加弯矩和位移,桩身沿隧道纵向的附加弯矩和位移相对较小;桩身最大弯矩和最大水平位移均发生在隧道中心线附近。与刀盘扭矩的影响不同,盾构推力主要使桩身产生沿隧道纵向的附加弯矩和位移;但桩身最大弯矩和最大水平位移也发生在隧道中心线附近。在风化岩地基中,刀盘扭矩对桩基沿隧道横向的影响是不可忽略的。

Based on the influence of the piles of a passenger station near the subway construction, FLAC-3D is a- dopted to make the numerical simulation and comparative analysis of the effects of cutterhead torque of shield and shield thrust on adjacent pile in decomposed rock foundation. Eight kinds of shield thrust and the cutterhead torque of shield used to this research. The results show that： it is different between the regularity of the impact of pile due to the cutterhead torque of shield and that due to shield thrust. The regularities of influence of pile due to the cutterhead torque of shield are： compared with the additional bending moment and horizontal displacement of pile along the lengthways direction of tunnel, the additional bending moment and horizontal displacement of pile along the horizontal direction of tunnel are principal ; the maximum bending moment and the maximum horizontal displacement of pile due to the cutterhead torque of shield both occurred near the eenterline of tunnel. Unlike the influence of cutterhead torque of shield, the additional bending moment and horizontal displacement of pile due to shield thrust are mainly produced along the lengthways direction of tunnel, but the maximum bending moment and the maximum horizontal displacement of pile due to shield thrust both also occurred near the centerline of tunnel. The above conclusions show that in decomposed rock foundation the influence of pile along the horizontal direction of tunnel caused by the cutter- head torque of shield can not be ignored.