ISSN 1000-3665 CN 11-2202/P

    层理灰岩酸性溶蚀损伤特性试验研究

    Experimental study on acid dissolution damage characteristics of bedded limestone

    • 摘要: 碳酸盐岩在我国西南地区广泛分布,其溶蚀特性为工程建设带来不少阻力。为研究层状碳酸盐岩在酸性溶蚀条件下的溶蚀损伤规律,采用自制流动溶蚀系统对4种不同条件下的层理灰岩进行室内溶蚀试验,获得层理灰岩溶蚀后的质量损失、纵波波速变化量、溶液中Ca2+和Mg2+质量浓度、表面溶蚀带形态特征等状态指标。采用层理灰岩溶蚀前后质量损失率定义损伤变量,通过多元统计回归分析方法,建立起4个不同自变量(层理倾角、pH值、溶液流速、溶蚀时间)和溶蚀损伤变量之间的关系,结果表明:层理灰岩的溶蚀损伤与层理倾角、溶液pH值、溶液流速、溶蚀时间之间存在良好的数学关系;溶蚀时间对层理灰岩溶蚀损伤有显著影响,溶液流速和pH值次之;不同层理倾角的灰岩,相同酸性环境下溶蚀效应呈现出90°>0°>45°>30°>75°> 15°>60°的规律;层理倾角对灰岩溶蚀影响较其他因素小,但是对岩样表面溶蚀形态起到了决定性作用。研究结果可以为灰岩地区工程实践和地质灾害防治提供一定参考。

       

      Abstract: In southwest China, carbonate rocks are widely distributed. It has unique dissolution features which bring a lot of resistance to engineering constructions. In order to explore the dissolution damage regular of layered carbonate rocks in acidic water, a self-made flow dissolution system was used to conduct laboratory dissolution tests on limestone cores under four different conditions. The mass loss, the change of p-wave velocity, the mass concentration of Ca2+ and Mg2+ and the morphology of the core surface were obtained. Mass loss rate after dissolution of layered limestone was used to define the damage variation. Through multivariate statistical regression analysis, the relationship between four different arguments (bedding dip Angle, pH, velocity of flow, dissolution time) and dissolution damage variation was established. The results show that the dissolution damage of layered limestone has a good mathematical relationship between the four different arguments. The following conclusions can be drawn from the analysis: The time has a significant effect on the dissolution damage of bedded limestone, followed by the velocity and pH. Under the same acidic environment, the dissolution effect shows a rule of 90° >0° >45° >30° >75° >15° >60° for limestone with different bedding inclination angles. The bedded angle has less effect on the dissolution of limestone than other factors, but plays a decisive role in the surface dissolution morphology of rock samples. The results of this study can provide some reference for engineering practice and geological disaster control in limestone areas.

       

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