深圳大运中心桩基施工过程中产生大面积塌陷,其建筑重要性、场地复杂程度、地基复杂程度均为一级,需对场地岩溶地面塌陷危险性进行评价,减少工程施工事故。采用高密度电法、地质雷达、层析成像、钻探等勘察方法查明土洞、溶洞发育特征,然后进行工程地质分析、建立土(溶)洞塌陷的静力学分析模型;分析影响岩溶塌陷的因素,建立包括岩溶基础条件、覆盖层特征、建筑物属性、水文地质条件4个一级指标及8个二级指标的岩溶塌陷危险性评价指标体系;基于MapGIS的数据管理系统,利用PLS Path Model(偏最小二乘通径模型)对场地岩溶地面塌陷危险性进行评价分区,并将地面塌陷危险性等级分为高、较高、较低和低4个等级,分别占场地总面积的1.05%,10.71%,19.39%和68.85%。评价结果客观、合理,其方法可为类似工程提供借鉴。

Collapse of large area occurred in Shenzhen universiade sports center during its pile foundation construction. Because the project is very important, and the ground and foundation are very complicated, we need to assess the hazard of karst ground collapse in order to reduce accidents. Firstly, we employed exploration methods inclusive of high-density electrical method, geologic radar, CT tomography, and drilling to investigate the development of soil holes and karst caves. On this basis, we built the statics model of the ground collapse through engineering geological analysis. Furthermore, we summarized the factors affecting the karst ground collapse and established a risk assessment index system based on the analysis of space distribution regularity of karst development and formation mechanism. The index system includes 4 first-level indicators (karst foundation condition, cover layer characteristics, building attributes and hydrogeological condition) and 8 secondary level indicators. At last, we adopted MapGIS and PLS (Partial Least Squares) Path Model to assess the hazard of karst ground collapse, and divided the ground collapse hazard into four levels: high, relatively high, relatively low and low, accounting for 1.05%, 10.71%, 19.39%, and 68.85% of the whole site respectively. The assessment and prediction results are objective and reasonable, and the proposed system can be used in similar projects.