铁路站场岩溶地基加固补强技术与效果分析

针对某病害站场路基，根据其变形规律对其基础进行补勘，分析病害原因，在此基础上提出岩溶地基加固补强方案：①补注浆加固岩溶地基和基岩顶面土体；②高压旋喷加固补强原复合地基；③低压注浆加固垫层及其以上3～5 m路基填土层；④侧向补注浆帷幕加固地基；⑤建立路基变形监测系统，评估加固补强效果。加固补强后地基沉降量和复合地基承载力特征值的理论计算值分别为12.4 mm和455 kPa，满足设计要求。现场监测结果表明，补注浆加固岩溶地基及其顶面土体后，站场路基变形减缓；旋喷桩和低压注浆加固区竣工后，路基呈均匀性沉降变形，变形速率急剧变小；竣工6个月后，路基变形趋于稳定，综合验证了加固补强方案的正确性和有效性。

Reinforcement technique and its effect analysis of karst foundation disease of railway station

Based on the deformation law of a station yard with subgrade disease, supplementary geological exploration and analysis are performed. A program of karst foundation strengthening is developed as follows. ①Strengthen karst foundation and soil on the top surface of bed rock through grouting. ②Strengthen the original composite foundation through high-pressure jet grouting. ③Strengthen the cushion layer and the soil layer 3-5 m above it by low-pressure grouting. ④ Strengthen karst foundation by the grouting curtain in the side of subgrade. ⑤Build a monitor system to estimate the strengthen effect. The calculation settlement and bearing capacity characteristic value of the strengthened subgrade is 12.4 mm and 455 kPa respectively, which can satisfy the design requirement of the subgrade. And the monitoring results show that the deformation of subgrade trends to be slower after the strengthening of karst foundation and soil on the top surface of bed rock; and the deformation presents wholeness with a sharply reduced deformation rate after the accomplishment of jet grouting piles and the reinforced area by low-pressure grouting. Six months after the reinforcement, the deformation trends to be steady, which certifies the validity and availability of the strengthening program.