【作者】 李军伟；

【导师】 李新生； 苏生瑞；

【作者基本信息】 长安大学 ， 地质工程， 2003， 硕士

【摘要】 地基沉降计算一直是困扰岩土工程技术人员的一个难题，其准确与否将直接影响建筑物的设计、施工和安全使用。在经典的地基沉降计算方法中，荷载作用下地基中附加应力场是根据半无限空间各向同性弹性体理论计算的，土体压缩性是根据一维压缩试验确定的，并采用分层总和法来计算地基的沉降量。这显然与土体实际应力状态及变形特性存在一定的差别。本论文正是基于这一思路开展研究的。希望通过分析土体受压后的变形特性和对沉降的原始数据处理与计算方法上的深入研究，以得出比传统的方法更加符合实际的地基沉降计算与预测方法。 本文主要由两部分构成：第一部分是在我们分析了土体受压后的变形特性，并在对其变形性质认识的基础上，建立了矩形面积均布竖向荷载下考虑侧向变形的地基沉降计算公式。通过实例试算，可知按照本文建立的计算方法在理论上可行，在实际工程中具有一定的参考价值，根据此方法计算得到的值不仅比较接近实测值和我们在后面论证的最优模型预测的结果，而且其值大于规范法所得，从安全角度来讲也比较可靠。 第二部分是沉降预测。针对地基沉降变形的影响因素众多，以及沉降与时间关系的复杂性，作者采用多种模型预测方法，并用C++编制了部分计算程序进行计算。在模型比选时，提出用实测值与预测值的后八项的平均误差，最大和最小误差来选择最优模型并判断其准确性以及实测数据选取的离散性。同时通过三个工程实例预测比较，证明GM(1，1)模型有较好的预测结果和稳定性可用于工程实践，也说明多模型的预测方法和判断结果是符合实际的。更多还原

【Abstract】 The calculation of the foundation settlement is always a difficult problem that puzzles researchers of geotechnical engineering. The precision of its calculating results has an direct effect on the design,construction and safe usage.In the typical calculation of the settlement of foundation, additional stress incurring by loading is calculated according to elastic theory which has the same characteristics in semi-indefinated space, the condesion of soil is decided by the condesion experiment of one-demension and the settlement is calculated by adding results of respective layer. Obviousely, it has difference between theory and realastic in stress and deformation to some extent. In order to overcome the disadvantages of the traditional calculating method,many researchers of geotechnical engineering like to use other calculating methods and analyze the oringinal settlement data to predict the settlement. Compared with the traditional calculating method, this method has the advantages of accuracy and convenience.There are two parts in this paper. In the first part, the deformaion behavior of soil loaded is analyzed. Then we construct the equation that considers the lateral deformaion of the settlement of foundation which is loaded by rectangle vertical equal loading through recongnizing the characteristics of deformation. In order to check the this method ,we apply it to the engineering example. Then we will find that the calculating result has more referring merits than method of the Code. The calculating result is not only same as the result of the model-predicting which is the best model we testmonied but also it is more safe than the method of the Code because it is larger.The second part studies the methods of settlement prediction. Because there are many factors that affect the settlement of soil.Furthermore, the relationship between timeand settlement is very complicated. In this paper we adopt the method that called the prediction method of multi-mthod and compile a program by C++ calculated for predicting. At the same timejt is proposed that the mean error ,maximum error and minimum error of the last 8 numbers between the measured results and predicting results are used as criteria in order that we can select the optimum model judge the accuracy and dispersion of measured results. Finally,by comparing with the predicting results of 3 engingeering examples,the prediction results of GM(1,1) model are proved to be better and more stability than other predicting models, the prediction method of multi- model and judging result are feasible.更多还原