Journal of Northeastern University(Natural Science) ›› 2022, Vol. 43 ›› Issue (7): 1019-1033.DOI: 10.12068/j.issn.1005-3026.2022.07.015

• Resources & Civil Engineering • Previous Articles     Next Articles

Water-Rock Mechanism of Weakly Consolidated Sandstone: a Case Study of Qingyang North Grottoes

ZHANG Jing-ke1,2, LIU Dun3, MA Yu-jun1,2, ZHANG Han1,2   

  1. 1. School of Civil Engineering and Mechanics, Lanzhou University, Lanzhou 730000, China; 2. Key Laboratory of Mechanics on Disaster and Environment in Western China, Ministry of Education, Lanzhou University, Lanzhou 730000, China; 3. China Railway First Survey and Design Institute Group Co.,Ltd., Xi’an 710000, China.
  • Published:2022-08-02
  • Contact: ZHANG Jing-ke
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Abstract: Qingyang north grottoes sandstone was selected as the research object, and two sets of single-factor weathering simulation experiments of freezing-thawing cycles and wetting-drying cycles for a total of 120d with 30 cycles were set up in laboratory. Combined with the deterioration characteristics of rock samples in different dimensions such as macro-scale, local scale, and micro-scale, as well as the migration patterns of surface mineral components and elements, the whole process of the water-rock interaction mechanism was tracked and evaluated. The experimental results showed that at the beginning of simulation experiments, the chemical interaction between water and rock was strong, and the chemical alteration coefficient of both groups increased sharply. With the cycles going on, the physical interaction between water and rock is getting stronger. The tensile and compressive stress are induced by the expansion of water volume between the particles during freezing-thawing cycles. The fracture was first induced at the part with highest moisture content. The granular structure is mechanically eroded by the flow of water during wetting-drying cycles, and the process is mutually controlled by moisture migration and pore distribution. For weakly consolidated sandstone, the key to sandstone deterioration is the change of particle coupling relation caused by frequent water-rock interaction.

Key words: weakly consolidated sandstone; Qingyang north grotto; freezing-thawing cycles; wetting-drying cycles; water-rock mechanism

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