摘要
依托广州地铁八号线盾构隧道侧穿华南快速高架桥桩基工程,分别对有无隔离桩支护桥桩的情况建立了有限元数值模型,研究了加固前后地表沉降、桥桩附加轴力、附加弯矩和桩身位移的变化并开展了加固优化设计。结果表明:隔离桩可有效减小既有桥桩垂直于掘进方向的桩顶位移,由于隔离桩的牵引作用,对于桥桩中部位移基本无削减作用,甚至极小地加大其水平位移;隔离桩基本消除平行于掘进方向的桥桩水平位移,对既有桥桩存在一定的遮蔽作用;隔离桩大幅减小了桥桩的附加轴力,大幅减小桥桩垂直盾构方向附加弯矩,对平行盾构方向附加弯矩基本无影响;适当提高隔离桩桩径以及隔离桩与桥桩之间的距离可以有效减小地表沉降,建议将隔离桩设置在离隧道净距为6~8 m内,既能满足规范要求的安全净距,也能较大限度保护既有桥桩。
Relying on the Guangzhou Metro Line 8 shield tunnel side-crossing the Huanan Express Viaduct pile project,and considering the situation of bridge piles with and without isolation piles,the finite element numerical model was established to study the ground settlement before and after reinforcement,the changes in additional axial force and bending moment of bridge piles,and the pile displacement.Then reinforcement optimization design was carried out.The results show that the isolation piles can effectively reduce the pile top displacement of existing bridge piles perpendicular to the driving direction.Due to the traction effect of the isolation piles,there is basically no reduction in the displacement of the middle of the bridge piles,and even a very small increase in the horizontal displacement.The isolation piles,which have a certain shielding effect on existing bridge piles,basically eliminate the horizontal displacement of bridge piles parallel to the driving direction.The isolation piles greatly reduce the additional axial force of the bridge piles,greatly reduce the additional bending moment of the bridge piles in the vertical shield direction,and basically have no effect on the additional bending moment in the parallel shield direction.Properly increasing the diameter of the isolation pile and the distance between the isolation pile and the bridge pile can effectively reduce ground settlement.It is recommended to set the isolation piles within 6 to 8 m away from the tunnel,so as to meet the safety net distance required by the specification and to protect the existing bridge piles to a greater extent.
作者
丰土根
况梦祥
沈正伟
张箭
张彦红
FENG Tugen;KUANG Mengxiang;SHEN Zhengwei;ZHANG Jian;ZHANG Yanhong(Key Laboratory of Rock and Soil Mechanics and Dyke Engineering,Ministry of Education,Hohai University,Nanjing,Jiangsu 210098,China;China Railway(Shanghai)Investment Group Co.,Ltd.,Shanghai 200126,China)
出处
《河北工程大学学报（自然科学版）》
CAS
2021年第3期55-62,共8页
Journal of Hebei University of Engineering:Natural Science Edition
基金
国家自然科学基金资助项目(51808193)
中央高校基本科研业务费资助项目(2019B07914)。
关键词
盾构隧道
侧穿桥桩
数值计算
隔离桩
加固优化
shield tunnel
side-crossing bridge piles
numerical calculation
isolation piles
reinforcement optimization
