江苏科技大学硕士学位论文参数法计算桩的水平内力姓名：曹骞申请学位级别：硕士专业：结构工程指导教师：汪宏20080101摘 要 桩本身由于制作简单，运输方便，便于机械化施工且抗弯抗压刚度大等特点得到了广泛的应用。目前随着港口码头、跨海大桥、海洋石油平台、高层建筑物和构筑物、柔性靠船结构物、护岸护坡结构、防滑结构物、深基坑支护等的蓬勃发展，这些建筑物或构筑物在波浪力、风力、地震力、冲击力、移动荷载等的作用下一般都承受较大的水平力， 所以这些建筑物或构筑物的基础桩基所承受的水平力受到了高度关注。 桩的水平力研究早期成果，国内外大同小异，现以我国为例。在线弹性地基反力法中的张有龄（1937）法，或称为张氏法、常数法，该法至今仍被有选择地使用，一般认为它比较适合于粘性土。因桩在地面处的挠度最大，故该法就有地面处土抗力最大的结论，有时不太合适，这是它的缺点。此外有 c 法、m 法以及地面至桩的挠度曲线的第一零点之间，土抗力集度 p 按二次抛物线分布，至第一零点以下土抗力模数为常数的 k 法。k 法因为在主要区段限定了土抗力集度 p 的分布图形， 而且硬性规定以桩的挠度曲线的第一零点作为土抗力模数的规律改变点，所以理论根据不足。由于以上方法只有一个参数，应用于弹性桩的计算时尚存在一些不足之处。其对桩在地面处的挠度、转角和弯矩的实测值只能凑合到接近的程度，如果用其中一个反算另一个其结果相差甚远。 最新研究成果有 PY 曲线法 、NL 法、港研法、双参数法，他们的计算结果比较接近实测值，但前几种计算方法，计算过程复杂且试验得到的土工参数人为因数较大。双参数法由于计算过程简单，计算精度很高，所以是一种值得推崇的方法。 综合刚度原理下的双参数法，由于推导正确、取值简单、与实测值吻合较好、克服了单参数法的缺陷且又可以退化成单参数法，所以越来越受到工程界的重视。然而，按目前所用的综合刚度原理双参数法所推导的公式，深度幂次数这个参数的取值只能为“1”和有限个正小数，这限制了参数的取值范围且与实际不符。加之在计算中对桩没有结合实际进行分段计算，而是对整个桩取统一参数计算，这就造成了桩的下半段误差较大。本文基于综合刚度原理，先对桩的求解表达式中深度的幂次数进行了修正， 推导了微分方程的解。 修正后的参数取值更广，甚至可以取到负值，这对于桩在小荷载作用下，原双参数由于取值限制无法求解的问题得以解决。通过实例计算发现，对于工程中最关心也是水平承载桩设计最重要的控制条件最大弯矩， 用本文的修正双参数法可以很好的算出各级荷载作用下的值，而且在地面处的转角，挠度值拟和也很好，对以前的单参数法是一个突破。在桩的上半段，用双参数法计算的精度是很高的，且算法是很稳定的。这对一般的工程设计来说，已经可以满足要求，但桩的后半段误差很大，说明双参数法有其局限性，在有些工程中，桩的后半段弯矩在安全，经济上是至关重要的。这是由于双参数法在计算桩的内力时，一直用同一参数，对桩没有分段计算，这与实际不符，造成误差累积加大。就算是对桩进行分段，取不同的参数，用双参数法再计算，误差还是较大，且修正的范围还不能很好的满足要求，这是因为对分界点以下计算时，参数取值还按分界点以上处理，实际上由于上部土的作用，分界点以下部分参数的确定是很复杂的。这就要求对桩的后半段重新求解，需要寻求一种可靠的方法。对桩进行分界点确定，运用反力积分法对桩的后半段进行计算是一种可靠稳定的方法。按刚性桩考虑由两端位移而引起的点的位移，按简支梁考虑由外力引起的点的位移， 按简支梁考虑由 n 个三角形分布的反力作用产生的点的位移相加就是桩各点的位移这就是反力积分法思想。 用反力积分法实例计算的结果表明，当双参数法计算值与实测值比较偏小时，反力积分法计算的值就会变大靠近实测值，使工程设计安全。当双参数法计算值与实测值比较偏大时，反力积分法计算的值就会变小靠近实测值，使工程设计经济。 关键词：关键词：综合刚度原理；双参数法；幂次数；反力积分法 Abstract Pile obtained the widespread application because it manufactures simply, transports convenient, is advantageous for the mechanized construction,is large in its anti-curved and anti-compressed. In recent years,with the development of cross sea big bridge, marine petroleum platform, high-rise building, the constructions of docking ship and so on, lateral supporting capacity of the pile was paid attention highly by pepole. Early time achievements of lateral force of the pile is mostly the same except for minor differences for domestic and foreign, presently taking our country as the example. “zhang you-ling” method is called “Zhang”the method or the constant method which is still used until now and considered quite suitable for the cohesive soil. Because of the pile be biggest in the ground amount of deflection, therefore, the constant method draws a conclusion that the ground earth resisting force is biggest. The conclusion is sometimes not too appropriate that is its shortcoming. In addition, there are the“c”method , the “m”method and the “k”method which earth resisting force collection “p”is two parabola distributions in the ground to between first zero of deflection curve of the pile and is constant in first zero below. the “k”law has defined the earth resisting force collection “p” distributed graph in the main sector, moreover,it takes first zero of deflection curve of pile as the earth resisting force modulus the rule change spot by the firm decision which the theory basis is insufficient. As a result of above several methods only then be a parameter, they are some deficiencies by application in the elastic pile computation.their calculating actual value only can assemble to the close degree in the ground amount of deflection, the corner and the bending moment. its result is far from actual value very much if we calculate out another with one. Newer achievements of lateral force of the pile have the PY curve method,the NL method,the port research method ,the biparameter method which the results are close to the measured values.But the first three methods are complex in calculating process and its earthwork parameter accuracy is decided in manifest human factors by the experiment acquisition. the parameter method is worth studying because its computing process is simple and computing precision is high. Biparameter method under composite stiffness principle is received the attention increasingly by engineering because it deduces correctly and approaches to actual values very much and overcomes the deficiencies of single parameter as well as degradation to single parameter. However, the power value of depth of the solution formula of biparameter method under composite stiffness principle currently only obtains “1”and limited positive decimal values that limits the scope of parameter and is impractical. Moreover, laterally loaded pile is not divided but the parameter is always used along whole pile, which will increase error of under half of the pile. Firstly ,in the paper, the power of depth of the solution formula of biparameter method under composite stiffness principle currently is revised and solution of differential equation is deduced and many examples is computed. parameter value is broader and it even may take the negative value after the revision which origina