【作者】 高庆丰；

【导师】 俞亚南；

【作者基本信息】 浙江大学 ， 市政工程， 2003， 硕士

【摘要】 受地理条件的限制，许多公路不得不建造在深厚的软土地基上。软粘土路基在外荷载作用下，其沉降一般是比较大，通常在建造前一般会进行较长时间的堆载预压，以消除大部分固结沉降和次固结沉降，尽管如此，路面的工后沉降仍然会在很长时间内继续存在。特别对于软土地基上的高等级公路，潜在的工后沉降将会对交通运输造成相当大的危害。因而有必要对软土路堤工程的工后沉降进行较为准确的预测，使得预测结果与实际结果更为接近准确以适时的提供日后维修解决工后沉降问题。因此，研究和建立软土路基工后沉降预测计算方法对我国快速发展的公路交通建设具有重要的实践意义。 文中首先基于Biot固结理论分别采用E-v非线性弹性模型和Merchant粘弹性模型两种模型有限元方法，根据施工期实测资料，采用直接优化反分析方法，分层分部反演地基土体的计算参数，然后计算路面铺筑后的工后沉降，并对将通过两个软土路基工程实践验证其可靠性。 文中对于多层软土地基多设计变量采用分层分部反演方法逼近全局最优解。针对粘弹性参数对沉降影响在固结后期才能明显表现，提出通过对不同时间段观测信息反演获得计算参数基本一致时，才可作为工后沉降预测的基本参数。通过实例反演应用，认为这些方法是可行的。 实际工程分析表明建立的有限元反演预测方法可行，但是软土不同的本构模型有其不同的适用性。由此，文中最后探讨基于实测数据处理方法应用于地基预测沉降方法。提出通过对预测模型的适应性检验，根据最小均方差自动选取预测模型的思想并编制程序。通过不同工程的不同断面实例验证，认为通过对观测数据进行系统分析处理来预测工后沉降不失为一种简便、实用的方法。更多还原

【Abstract】 Many highway construction have to be built on thick soft clay foundation .the soft foundation has large settlement under load. Because the high pore-water ratio,lower strength,high compression all are the characteristics for the soft foundation. Therefore,per-loading technique is usually adopted to get rid of most deformation due to primary and secondary consolidation before construction. Even so,the foundation settlement after construction will exist for a long period. And in this paper,the prediction method of the foundation settlement after construction is discussed.Firstly,two-dimensional formulas of Biot’s consolidation FEM base on nonlinear hyperbolic model and Merchant’s model are presented to calculate settlement of saturated soft clay ground. Form the observation date obtained during construction,the geological parameters may reasonably be determined by direct optimal method such as Powell so that it minimizes the squares of differences between calculated and measured quantities (objective function). Adopting FEM and the roadbed settlement after construction is calculated. Then a back analysis program of FEM for soil is given. The back analysis was performed for two highways based on the program and the results were obtained.In addition,the application of the date process in foundation settlement prediction is presented at the end of this paper. Based on the exponential method,hyperbolic method,GM method,the idea to select calculating model automatically in the light of least deviation is raised. Base on this idea,a forecast program is developed. The actual detection data show that the program is effective and practical.更多还原