中文摘要：

涵洞属于填埋式构造物,其受力状态不同于普通建筑物。对涵-土体系作用机制认识不足和涵洞地基处理不当可能导致涵洞出现各种各样的病害,甚至影响道路运营。通过现场测试和数值模拟分析了上埋式钢筋混凝土拱涵结构与土体的作用机制,得出了涵-土体系的受力状态和变形特性。在此基础上对涵洞地基处理进行了研究,分析了地基处理的宽度、深度以及处理后的地基刚度对涵洞受力状态和变形特性的影响。研究结果表明,涵顶存在明显的应力集中现象,该效应的影响范围为涵洞两侧约3b（b为涵洞宽度）;涵顶土压力系数随填土高度的增大而增大,并逐渐趋于稳定;涵顶土压力、基底压力和涵洞结构内力随地基处理宽度的增大而减小,并逐渐趋于稳定,随地基处理深度和地基弹性模量的增加呈非线性增大。实际工程中,涵洞地基处理宽度宜取b＋2h（h为涵洞高度）左右,地基处理的深度和处理后的刚度应以允许沉降或差异沉降为控制指标,不应额外增加地基处理深度和提高地基刚度。

英文摘要：

Culvert belong to buried construction,of which the stressing state is different from the buildings.With poor understanding on the mechanisms of the soil-culvert system and improper ground treatment of culvert,many geotechnical and pavement problems occurred for culverts during the construction process or under service conditions.In this study,field test and numerical simulation are conducted to investigate the mechanisms of soil-culvert system,the stressing state and deformation characteristics of which are obtained.Moreover,the ground treatment of culvert is also studied based on the fore-researches.Especially,the influence of ground treatment area and the ground stiffness of treatment area on the stressing state and deformation characteristics of soil-culvert system are analyzed by numerical simulation.This research reveals that vertical earth pressure is obviously concentrated on the crown of culvert;the influencing area is about 3b（b is the width of culvert） on the both sides of the culvert axes.The coefficient of earth pressure on the culvert crown increases with the height of fill,but it＇s likely to approach a limit value at a higher fill.The vertical earth pressure on the culvert crown,the foundation pressure of culvert,as well as the internal forces of culvert decrease with increasing the ground treatment width and gradually tend to limit values;but they are nonlinearly increase with increasing the ground treatment depth and the ground stiffness of treatment area.It is suggestion that,in practical engineering,the ground treatment width should be about b＋2h（h is height of culvert）;the ground treatment depth and the ground stiffness of treatment area should be controlled by allowable settlement and/or differential settlement,but the ground treatment depth and the ground stiffness should not be increased extraneously.