娄新高速公路岩溶发育特征与地基处理方案优化研究

娄底—新化高速公路岩溶发育。由于邻近煤矿采矿抽排水，地下水位急降，形成土洞和塌陷。为保证公路建设经济、安全，须对岩溶路基进行处理。通过对地基处理方案影响因素进行研究与分析，运用多目标决策模糊集理论并结合层次分析方法，优选出具有多指标因素属性和模糊特性的岩溶地基处理方案。在此基础上，从地质条件出发，并考虑加固效果、工程造价等，比较了3种岩溶地基处理方案：注浆、沉管挤密桩、强夯+双层钢筋混凝土连续板。分析结果表明：强夯+双层钢筋混凝土连续板方案最佳，模糊优化计算中，该方案对优的隶属度最高，达0.86，具有施工便捷、加固效果好、成本低等优点，总造价为仅1 350万元，分别比沉管挤密桩、注浆处理少170万和360万元。

Karst features and optimization of karst foundation treatment in Luodi-Xinhua Expressway

Karst is developed in Luodi-Xinhua Expressway. Earth-caves and karst collapses are formed with groundwater table rapidly falling led by mining and pumping in the surrounding coal mine. In order to make the construction of expressway economically and securely, the karst subgrade is necessary to be treated. Firstly, through study and analysis on the factors affecting the foundation treatment, a foundation treatment scheme with multiple attribute and fuzzy property is optimized by means of multi-objective decision making fuzzy set theory and analytical hierarchy process. Secondly, based on the engineering geological conditions and the reinforcement effect as well as engineering cost, three schemes of karst foundation treatment are compared, including static pressure grouting, tube sinking compacted gravel piles and dynamic compaction with reinforced concrete continuous plate. The results show that the dynamic compaction with reinforced concrete continuous plate is the most optimal scheme which is of the highest degree of membership to excellence (up to 0.86), the lowest cost (only 13.5 million yuan) and good reinforcement effect. The cost, 13.5 million yuan, is respectively 1.7 and 3.6 million yuan less than the tube sinking compacted gravel piles and the static pressure grouting schemes.