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期刊论文 2

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2010 1

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A hypothesis for crack free interior surfaces of Longyou caverns caved in argillaceous siltstone 2000

Zhong Qi YUE, Shaopeng FAN, Zhifa YANG, Lihui LI, Luqing ZHANG, Zhongjian ZHANG,

《结构与土木工程前沿（英文）》 2010年 第4卷 第2期   页码 165-177 doi: 10.1007/s11709-010-0018-1

摘要： Five complete caverns were discovered in Longyou in 1992. They were manually caved in argillaceous siltstone at shallow depths more than 2000 years ago. When they were un-watered, their integrity was maintained completely, and their interior rock surfaces were free of old cracks. Since then, however, the rock’s interior faces have initiated and propagated more and more cracks. This paper attempts to address the question of why the rock interior faces were free of old cracks once they were unearthed. To address this question, this paper proposes a hypothesis that the argillaceous siltstone has the ability of self-healing its cracks over a short period of time under weak acid water environment. Data and evidence are presented herewith to prove the hypothesis. They include observations and measurements in the field and test results in the laboratory. Specifically, a three-point bending test is used to form a tensile crack in a rectangular rock specimen and a dead load test for the specimen immersed in initially weak acid water is used for self-healing its crack. The results have shown that the argillaceous siltstone is in a state of weak alkalinity and the rain water at the site is in a state of weak acidity. Therefore, when it is immersed in weak acid water for some time, the argillaceous siltstone would be able to make chemical reactions to generate new minerals such as calcite. The new minerals would be able to infill the cracks and then heal the crack within a few years. Once the crack is self-healed, the rock can regain its strength and integrity. Consequently, the rock interior surfaces could be free of old cracks when the water was pumped out of the caverns.

关键词： rock cavern     grotto     Longyou     argillaceous siltstone     crack     water     environment     self-healing    

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Clogging of slurry-shield tunnel-boring machine drives in sedimentary soft rock: A case study

《结构与土木工程前沿（英文）》 doi: 10.1007/s11709-023-0984-8

摘要： This paper presents a case study of the clogging of a slurry-shield tunnel-boring machine (TBM) experienced during tunnel operations in clay-rich argillaceous siltstones under the Ganjiang River, China. The clogging experienced during tunneling was due to special geological conditions, which had a considerably negative impact on the slurry-shield TBM tunneling performance. In this case study, the effect of clogging on the slurry-shield TBM tunneling performance (e.g., advance speed, thrust, torque, and penetration per revolution) was fully investigated. The potential for clogging during tunnel operations in argillaceous siltstone was estimated using an existing empirical classification chart. Many improvement measures have been proposed to mitigate the clogging potential of two slurry-shield TBMs during tunneling, such as the use of an optimum cutting wheel, a replacement cutting tool, improvements to the circulation flushing system and slurry properties, mixed support integrating slurry, and compressed air to support the excavation face. The mechanisms and potential causes of clogging are explained in detail, and the contributions of these mitigation measures to tunneling performance are discussed. By investigating the actual operational parameters of the slurry-shield TBMs, these mitigation measures were proven to be effective in mitigating the clogging potential of slurry-shield TBMs. This case study provides valuable information for slurry-shield TBMs involving tunneling in clay-rich sedimentary rocks.

关键词： slurry-shield TBM     geological investigation     clogging     argillaceous siltstone     TBM performance     mitigation measures    

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标题 作者 时间 类型 操作

A hypothesis for crack free interior surfaces of Longyou caverns caved in argillaceous siltstone 2000

Zhong Qi YUE, Shaopeng FAN, Zhifa YANG, Lihui LI, Luqing ZHANG, Zhongjian ZHANG,

期刊论文

Clogging of slurry-shield tunnel-boring machine drives in sedimentary soft rock: A case study

期刊论文