桩间加固土参数对双排桩支护结构的影响分析

Analysis of the Influences of Reinforced Soil Parameters between Piles on Double Row Pile Supporting Structure

以武汉市铁路桥地下净水厂基坑工程为背景,采用三维弹塑性数值模拟的方法,对基坑双排桩支护开挖深度最大的标准段开挖过程进行模拟。在通过对比现场实测结果、设计软件计算结果和数值计算结果验证了数值模型合理性的基础上,分析了桩间土加固深度、弹性模量、黏聚力及内摩擦角对双排桩支护体系承载变形特性的影响。研究结果表明,双排桩桩间土加固对支护体系变形的控制效果显著,但桩间土加固深度和弹性模量存在一个有效范围,当超出该有效范围后,加固效果的提高幅度不显著;对于支护桩弯矩和支撑轴力而言,桩间加固体的深度存在最优值;增大桩间加固体黏聚力及内摩擦角能够有效提高支护体系抵抗变形的能力。

Based on the foundation pit engineering of Wuhan railway bridge underground water purification plant,the excavation process of the standard section with the maximum excavation depth of double row piles is simulated by using the method of three-dimensional elastoplastic numerical simulation.On the basis of verifying the rationality of the numerical model by comparing the field measurement results,the design software calculation results and the numerical calculation results,the influence of reinforcement depth,elastic modulus,cohesion and internal friction angle of soil between piles on the bearing deformation characteristics of the double-row pile support system is analyzed.The results show that the soil reinforcement between piles of double row piles has a significant effect on the deformation control of the supporting system.However,there is an effective range of reinforcement depth and elastic modulus of soil between piles,beyond which the improvement of reinforcement effect is not significant.For the bending moment and supporting axial force of supporting pile,the depth of strengthen solid between piles has an optimal value.Strengthen solid cohesion and internal friction angle between piles can effectively improve the ability of supporting system to resist deformation.