水平静力荷载作用下桩伴侣工作性状有限元模拟及与无伴侣构造形式的比较分析

摘要

Reference on lateral load test and numerical simulation of large diameter pipe pile by using cast-in-place concrete(PCC),finite element model of a single pile with or without pile partner under lateral load is established. Comparison calculations show that pile partner can ensure lateral loads delivering from pile cap to foundation soil, and double reduce stress and displacement of pile. Pile partner can also make some improvement on lateral bearing characters for the pile foundation with low cap even though the modulus of foundation soil is small. When pile partner is equipped,and the connection mode between pile cap and pile changing from rigid connection to hinge joint,pile body internal force can also be drastically reduced;and pile and pile caps by distance can only be considered to meet the requirement of vertical bearing capacity or optimization design of pile foundation stiffness to reduce differential settlement. Pillow is not necessary and can be cancelled in composite foundation when pile partner is applied. The height of pile partner has little influence on internal force and displacement of pile. Under rare earthquake action,pile partner may sacrifice firstly to keep pile perform well.%借鉴现浇混凝土大直径管桩(PCC 桩)水平承载足尺试验和数值模拟的成果，建立水平荷载作用下多个构造形式有无伴侣的单桩有限元数值模型。对比计算与分析表明，对于低承台桩基设置桩伴侣可确保承台向地基土传递水平荷载，成倍减小基桩的应力和位移；对于桩身范围地基土模量低的低承台桩基的水平承载性状也有一定的改善；配备桩伴侣后，将桩与承台的连接方式由刚接改为铰接也能大幅度减小桩身内力，桩顶与承台的距离可单纯考虑竖向承载力和变刚度调平基础底板沉降的需要；设置桩伴侣后可取消褥垫层；桩伴侣的高度变化对水平荷载作用下桩内力和位移影响很小；在罕遇地震等荷载工况下，桩伴侣可作为耗能构件，首先牺牲伴侣，避免或延迟桩头的破坏。