摘要
将结构力学方法和改进的“m法1理论”引入到双排基坑支护桩的计算中。本文提出改进的“m法1理论”，将双排桩的前排桩和单排桩的计算坐标原点取在坑底处，将坑底以上的桩后土在坑底以下桩上产生的土压力考虑在桩的挠曲微分方程中。其坑底以上的土压力为位移、排桩净距和土性指标的函数，其坑底以下由于坑底以上土的重力产生的土压力为位移、排桩净距和土性指标的函数，但将坑底以下多层土换算为单层土，坑底以下产生的这一土压力便可取为常数。上述土压力与位移的关系式通过试算确定。通过室内模型试验、双排桩改进的“m法1理论”，得到如下一些可资参考的结论：（a）只要桩顶连梁与桩的刚度比等于0．48，则连梁刚度是合适的，再继续增加连梁刚度无意义；（b）按照公路、铁路桥涵规范确定的桩间不相互影响的排桩净距值偏于保守，不同的土类可乘以0．81～0．92的系数，粗粒土乘0．81，细粒土乘0．92，继续增大排桩间净距对双排桩的受力和变形影响不大；（c）本文的工程实例表明双排桩较单排桩至少可减少造价22％，具有良好的经济价值，同时具有良好的变形性能，对基坑周围建筑物（构筑物）或地下管线不构成影响，值得继续研究和广泛应用于各种支护工程中。
The method of structural mechanics and the perfect ＂ml theory＂ were introduced to the double-row retaining piles. The perfect ＂ml theory＂ can be applicable to the single-row pile and the front row pile of the double-row retaining piles. The earth pressure below the pit and above the pit in the back of the single-row pile and the front row pile caused by the soil above the pit was considered in the differential equation of pile. This earth pressure is the function of displacement, net distance between the double-row piles and the engineering character of the soils. The relation of earth pressure with above factors is gained through tentative calculation. The model test and the calculation completed result in following results： （a）it is suitable that the rigidity ratio of the top girder to the piles is not less than 0.48 and to further increase the ratio does not have any biggish benefit; （b） the net distance between the double-row piles, which does not influence each other, is some bigser than the fact,and it is better to reduce this value down to 0.81 - 0.92 time based on the bridge criterion; （c） the double-row piles are of cost saving and have strong capability of resisting deformation, It＇s worthy of further research and extensive application.
出处
《建筑科学》
北大核心
2008年第11期60-65,共6页
Building Science
基金
贵州省委组织部高层次人才科研特助项目(项目号Z053126)
关键词
双排支护桩
支护机理
改进的“m法1理论”
局部土体的库仑土压力
double-row retaining piles
retaining pile＇s mechanism
the perfect＂m-method 1 theory＂
Coulomb soil-pressure of part soil
