反力弹簧法解双排桩结构内力

Internal Force Analysis of Double-Row Piles Using Concentrated Spring Method

双排桩反力弹簧法是在比例系数法的基础上结合排桩反力弹簧原理提出的1种新的计算双排桩结构内力的方法。采用反力弹簧模拟双排桩入土部分的土、桩共同作用问题,不同的土层选用不同刚度的弹簧进行模拟,使得双排桩支护结构简化为1个受多个弹簧约束的超静定门字形刚架,然后根据结构力学力法原理进行分析计算,即可求得双排桩结构内力。与常规的比例系数法相比较,用反力弹簧法求解双排桩结构内力,无需假设和考虑结构嵌固点,可以准确描述土的变形情况和考虑土体的分层情况。运用推导出的反力弹簧法求解双排桩结构内力计算公式,进行双排桩实例分析计算,计算得出的弯矩(应力)分布规律与现场测试结果基本吻合,说明应用反力弹簧法计算分析双排桩结构内力是可行的。

Double-row concentrated spring method, which is the combination of inverse proportion coefficient method and row piles concentrated spring method, is a new method proposed to calculate the internal force of double-row piles. Concentrated spring method is used to simulate pile-soil interaction of the part of double-row piles in the soil. Different rigid spring is adopted to simulate different soil. The support structure of double-row piles can be simplified into a statically indeterminate portal rigid frame which is restricted by many concentrated springs. Then the internal force of double-row pile structure can be obtained through analysis and calculation based on the force method principle of structure mechanics. Compared with the conventional inverse proportion coefficient method, by using concentrated spring method to solve the internal force of double-row piles, soil deformation can be accurately described and the layer state of soil mass can be calculated without assuming and considering the embedded point of the bracing structure. Moreover, the formula for solving the internal force of double-row piles is given by using the deduced concentrated spring method. Example of double-row piles project is analyzed and calculated by the aforemen- tioned method, and the distribution of moment （stress） obtained by calculation basically agrees with field test result. This indicates that it is feasible to use concentrated spring method to calculate the internal force of double-row piles.