Taking dolomite and limestone in Guilin and Liuzhou regions in the north of Guangxi Province as research objects, this paper analyzed their mineral composition and chemical composition, and then carried out the chemical corrosion test, the corrosion test under the chemical-temperature actions, and the corrosion test under the action of vibration load, respectively. The results showed that: (i) the dolomite in northern Guangxi mainly has fine crystalline texture and massive structure with low content of acid insoluble matters, while limestone mainly has powder crystalline texture and massive structure with high content of acid insoluble matters, and the purity of both dolomite and limestone are very high; (ii) the difference of corrosion between dolomite and limestone mainly depends on the ratio of CaO/MgO in their chemical composition, and the content of silica and acid insoluble matters; (iii) the corrosion rates of the pure dolomite and the pure limestone are basically the same under the same external conditions; (iv) temperature and vibration load have relatively large influence on the corrosion rates of dolomite and limestone, and the corrosion rates of dolomite and limestone increase with the increase of temperature, but the influence of vibration load on the corrosion rate is more significant than temperature. This research can provide theoretical basis and technical support for large-scale engineering construction and prevention of karst geologic disasters in karst stone mountainous areas in the northern Guangxi.
Keywords: dolomite and limestone; structural features; corrosion characteristics; northern Guangxi
The frequent vibration loads during the operation of trains can cause vibration deformation of the tunnel structure and surrounding weak strata, thereby endangering the safe operation of trains. The purpose of this paper is to study the dynamic response of surrounding soil layers caused by train vibrations through the finite difference method with FLAC3D. Based on existing research, we studied the artificially deterministic exciting force function. Then, we simulated the tunnel working conditions of a train with a 3D model, and applied the artificially deterministic exciting force function to the tunnel model. To study the vibration caused by trains in silty soil, we divided the trains into two cases, one-way and two-way. We compared the displacement–time curves of one-way and two-way trains. When the horizontal distance between the monitoring point and the vibration source increases, the peak value of the displacement–time curve decreases. As the speed of the train increases, the peak value of the displacement–time curve increases. The vertical displacement of the ground under the dynamic load of the two-way train is greater than that of the one-way train. In the acceleration–time curve, there is a lag in the ground acceleration response. The faster the speed of the subway train, the greater the peak value of the acceleration–time curve. This study can provide a guide for the evaluation and prevention of ground vibration subsidence and uneven subsidence of strata in the silt area of the Yellow River Region.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.