改革开放30多年来我国经济得到了快速发展，基础设施建设不断扩大，已建成的高速公路益增多，由于道路地质条件的复杂性，既有高速公路出现了各种病害，使得高速公路路基治理技术得到了快速发展。当前高速公路路基病害治理措施中，碎石注浆桩应用很广泛，但是其理论研究远落后于实践，其工作机理需要进一步研究。为了更好的推广和应用碎石注浆桩处治公路沉降病害技术，对其适用条件及承载特性需要更深入的分析研究。 本文以河北省G308线石邢界至石家庄段公路工程病害为背景，针对石邢界至石家庄段公路工程病害的具体特征，系统分析了公路工程病害产生的原因；同时研究分析了干拌碎石+注浆成桩加固机理，通过现场试验及数值模拟方法对桩长、桩间距、桩体模量等参数进行桩的承载力分析，得出如下结论： （1）分析勘探取样及探地雷达检测结果，得到G308公路石邢界至石家庄段（K639-K641段）浅层滞水现象严重，路面结构遭到水的侵蚀，强度下降范围大，抵抗变形能力弱，这是路面出现病害主要原因。本文采用干拌碎石+注浆成桩法修复加固公路路基，并介绍了干拌碎石+注浆成桩的特征与设计计算。 （2）本文通过 FLAC3D 所建立的有限元数值分析模型，对干拌碎石注浆桩现场静载荷试验进行了模拟分析，并得到与现场试验较为吻合的模拟结果，同时模拟分析干拌碎石注浆桩对路基的加固效果，研究在标准荷载以及超载作用下的沉降变形，对比分析了不同因素下对加固效果的影响大小。 （3）采用数值模拟计算，通过考虑群桩复合地基承载特性的复杂性，研究了不同桩长、桩间距的布桩形式对复合地基路基和路面沉降的影响，最后得到较合理的群桩复合地基设计参数。

Over the past 30 years of reform and opening-up, China’s economy has developed rapidly, infrastructure construction has continued to expand, and the number of expressways built has been increasing. Due to the complexity of road geological conditions, various diseases have appeared on existing expressways, thus leading to the rapid development of highway subgrade treatment technology. Among the current highway subgrade disease control measures, gravel grouting pile is widely used. But the theoretical research of it is far behind practice, and its working mechanism needs further study. In order to better promote and apply gravel grouting pile in the treatment of highway settlement diseases, the applicable conditions and bearing characteristics of it need to be further analyzed. Taking the highway engineering diseases of Shijiezhuang-Shijiazhuang Section of the G308 line in Hebei Province as the background, the causes of highway engineering diseases were systematically analyzed in the thesis according to the specific characteristics of them of the above section. And the mechanism of dry-mixed gravel + grouting piles was studied and analyzed at the same time. Through field tests and numerical simulation methods, the bearing capacity of piles was analyzed by parameters such as pile length, pile spacing and pile modulus, and the following conclusions were reached: （1）From the analysis of the results of exploration sampling and ground penetrating radar detection, the shallow water stagnation phenomenon of the Shijiazhuang-Shijiazhuang Section of the G308 line (K639-K641) was severe, and the pavement structure suffered from water erosion. The dropping range of intensity was large, and the resisting ability to deformation was weak, which was the main cause of pavement disease. In this paper, the method of dry-mixed gravel + grouting piles was used to repair and reinforce the highway roadbed, and the characteristics and designing calculation of it were introduced. （2）In this paper, through the finite element numerical analysis model established by FLAC3D, the static load test of dry-mixed gravel grouting piles was simulated and analyzed, and the simulation results in line with field tests were obtained. Meanwhile, the reinforcement effect of the dry-mixed gravel grouting piles on highway roadbed was simulated and analyzed, the settlement deformation under standard load and overload was studied, and the influence of different factors on the reinforcement effect was compared and analyzed. （3）By using numerical simulation calculations and considering the complexity of the bearing characteristics of the group piling composite foundation, the effects of the piling form under different length and spacing on the roadbed and pavement settlement of the composite foundation were studied, and eventually, comparative reasonable designing parameters for the group piling composite foundation were obtained.