摘 要 近年来，在公路建设中，对软土地基采用了不同的处理措施，但是鉴于公路施工工期要求比较紧，有一部分软土地基问题是在施工期间发现的，因此，直接快速地处治软土地基显得越来越重要。河北省中部地区为冲积平原地貌特征，软弱地基上普遍存在上覆硬壳层，快速补强下伏软土地基，提高土体的力学强度和变形模量，减少总的沉降量，满足高速公路路堤沉降和稳定性的要求势在必行。根据该公路施工过程中的工期要求以及施工条件，对其中三段软土地基采用注浆的方法进行处理，由于在不扰动上覆硬壳层的前提下采用注浆处理软土地基较为少见，因此，开展了相应的试验研究。 本研究以河北省廊沧高速公路为背景，在分析该高速公路软土地基路段的具体的工程地质条件基础上，对软土地基注浆方法进行了系统的研究，获得了如下成果： （1）研究试验段工程地质特征：在分析该试验段地质与工程地质条件的基础上，选择典型路段进行路基稳定性计算与分析评价。针对工期时间要求短，施工现场有高压线等不利条件，通过比对分析后，采取注浆技术作为直接快速的地基处理方法。 （2）对试验段软土地基注浆加固技术进行试验研究：通过试验工程的实施与研究，提出适合于该地区的注浆加固边界范围与注浆参数，适合应用的浆材、配比与注浆工艺。 （3）结合工程实际，从注浆方式和注浆压力两方面对注浆扩散过程进行了数值模拟分析，并从天然状态和注浆结束后两方面对软土地基性态进行了模拟分析，模拟验证注浆的参数的选取和注浆效果，得出注浆提高了地基承载力、改善了物理力学性质的结论。 （4）对该注浆工程所达到的效果作出了综合评价。注浆治理后的地基承载力和安全系数均满足一般路基的沉降和稳定性要求，在快速补强此类软土地基的处理方法中，注浆法较为合理。 通过该研究，不仅能解决有关设计理念、工艺方法、检测内容等问题，而且能为高速公路软土地基加固应急工程提供一条经济上合理、技术上可行且直接快速的技术措施，该治理技术将为今后直接快速地处治软土地基提供有益的借鉴。

ABSTRACT Recent years, different measures have been used to deal with the soft soil foundation in freeway construction. Usually it has limited construction time, and some problems is discovered during the constuction. Therefore, treated the soft soil foundation directly and quickly has become increasingly important. In central of Hebei Province, the geomorphological characteristic is alluvial plain. The hard crust is widespread in the soft foundation of this area. It is imperative to reinforce the soft soil foundation quickly, improve the mechanical strength and deformation modulus of the soil, reduce the total settlement, meet the enbankment settlement and stability of freeway. According to the period requirement and construction conditions, used grouting method to treat three sections of this freeway. Until now there are few people who used this method to treat the soft soil foundation without disturbed its crust, so, the correponding experiment has been done on this method. In this study, the research background is langcang freeway of Hebei Province. Based on the analysis of the engineering geological conditions of this freeway, the grouting method has been researched systematically, and obtained results as follows. (1) Studied the engineering geological characteristics of the test section: Selected typical sections to calculate and evaluate the stability of the subgrade which based on the analysis of the geological and engineering geological conditions of the test section. According to the unfavorable conditions of a short period and the high voltage wire in the construction site, and after comparatively analysing the methods of foundation treatment, the grouting is used in this area. (2) Researched the grouting of soft soil foundation of the test section: Through implementing and researching the test engineering, proposed suitable grouting boundaries and parameters, and suitable grouting material, mix proportion and process. (3) Combined with the project fact, numerical simulation anlysis is used to study the process of grouting from methods and pressures of the grouting, and simulated the behavior of the soft soil foundation from natural state and end of grouting. Verified the parameters of grouting and the effect. The result is that the grouting has improved the bearing capacity and physical and mechanical properties. (4) Made a comprehensive evaluation of the perfermance of this construction engineering. The result showed that the bearing capacity and the safety factor have met the requirement of settlement and stability. The grouting is more reasonable than other methods in reinforcing such soft soil foundation quickly. The study not only can solve the design, process methods, contents of detecting etc. But also can provide a economically reasonable, technically feasible and rapid measure to the emergency project of strengthening the soft foundation of freeway. This control technology will provide useful reference for the future soft soil treating.