Experimental study on karst development characteristics of calcrete and analysis of its dissolution mechanism
Experimental study on karst development characteristics of calcrete and analysis of its dissolution mechanism
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DOI：
10.1007/s13146-022-00787-0
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发表时间：
2022-05
影响因子：
1.4
通讯作者：
Kegang Zhang;Kao-fei Zhu;Yong He;Yun-yi Zhang
中科院分区：
文献类型：
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作者：
Kegang Zhang;Kao-fei Zhu;Yong He;Yun-yi Zhang
岩溶在世界范围内分布广泛，对生态环境和工程建设都有重大影响。通过野外调查，建立了浏阳河附近钙质混凝土岩溶的三维地质模型。通过薄片鉴定、X射线衍射（XRD）和电子探针（EPMA）分析，研究了钙质结砾岩的结构和矿物组成。通过溶蚀试验和单轴抗压强度试验，分析了钙质结砾岩的岩溶发育特征和溶蚀机理。实验结果表明，钙质砾岩岩溶主要分布在河流附近，发育规模较小，85.96%的溶洞充填有砾石和粘土。钙质结砾岩的胶结成分主要为方解石，约占20%。同时，钙质结砾岩中含有大量不溶性碎屑颗粒，经溶解后沉积于溶洞中。溶蚀试验结果表明，方解石胶结物的溶蚀破坏了岩石结构。石灰岩的溶蚀速率随H+浓度的增加而线性增加，岩石强度随岩溶作用而降低，注浆加固充填物是治理石灰岩岩溶的有效方法。这些研究成果对钙质混凝土岩溶地质研究具有重要的理论意义，对工程建设具有很强的实用价值。
Karst is widely distributed throughout the world and has a significant impact on the ecological environment and engineering construction. In this study, a 3D geological model of calcrete karst near the Liuyang River was established through field investigation. The texture and mineral composition of calcrete were investigated by thin section identification, X–ray diffraction (XRD) test, and electron probe microanalysis (EPMA). Moreover, dissolution tests and uniaxial compressive strength tests were performed to analyze the karst development characteristics and dissolution mechanism of calcrete. Experimental results demonstrated that the calcrete karst is primarily distributed near the river with a small development scale, and 85.96% of the caves are filled with gravels and clay. The cementation component of calcrete is mainly composed of calcite, accounting for approximately 20%. Meanwhile, calcrete contains a large number of insoluble clastic particles, which were deposited in the karst caves after dissolution. The dissolution test results revealed that the dissolution of calcite cement destroyed the rock texture. The dissolution rate of calcrete increased linearly with increasing H+concentration.In addition, the strength of rock decreased with karstification, and grouting was effective in treating calcrete karst by reinforcing the fillings. These findings are theoretically important for calcrete karst geology research and highly practical for engineering construction.