Microstructure analysis and mechanical parameter estimation of sanding dolomite

Sanding dolomite strata are widely distributed in southwest China. The safety of the water diversion tunnel in Yuxi section of the Central Yunnan water diversion Project has been seriously threatened by the geological disasters such as the reduction of rock strength caused by dolomite sanding and tu...

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Main Authors: Fengnian Wang, Zewei Li, Yongxiang Shi, Xiaowen Gong, Yanjie Zhang
Format: Article
Language:English
Published: Frontiers Media S.A. 2025-03-01
Series:Frontiers in Earth Science
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Online Access:https://www.frontiersin.org/articles/10.3389/feart.2025.1522361/full
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author Fengnian Wang
Fengnian Wang
Fengnian Wang
Fengnian Wang
Zewei Li
Zewei Li
Yongxiang Shi
Yongxiang Shi
Xiaowen Gong
Yanjie Zhang
author_facet Fengnian Wang
Fengnian Wang
Fengnian Wang
Fengnian Wang
Zewei Li
Zewei Li
Yongxiang Shi
Yongxiang Shi
Xiaowen Gong
Yanjie Zhang
author_sort Fengnian Wang
collection DOAJ
description Sanding dolomite strata are widely distributed in southwest China. The safety of the water diversion tunnel in Yuxi section of the Central Yunnan water diversion Project has been seriously threatened by the geological disasters such as the reduction of rock strength caused by dolomite sanding and tunnel sand inrush. In order to explore the mechanical characteristics and obtain the mechanical parameters of sanding dolomite quickly and accurately, this study relies on the Central Yunnan Water diversion Project to first established the classification standard of dolomite sanding grade. The pore structure, microscopic composition and morphological distribution of dolomite with different sanding degrees were studied by means of SEM scanning, EDS spectroscopy and CT scanning. At the same time, based on the field needle penetration test and the Hoek-Brown strength criterion considering the wave velocity and integrity coefficient of rock mass, a method for estimating the mechanical parameters of sanded dolomite was proposed, which was verified by NPI test and field adit test. The results showed that the sanding dolomite could be divided into four grades: slight sanding dolomite, moderate sanding dolomite, strong sanding dolomite and severe sanding dolomite. The higher the sanding grade, the higher the development degree of dolomite pores and the lower the mechanical strength. The action of groundwater will aggravate the dolomite dissolution sanding and lead to the aggravation of surrounding rock breakage. Based on the improved Hoek-Brown strength criterion, the cohesion of strong sanding dolomite is 0.34∼0.71 MPa, the internal friction Angle is 38.59∼50.96°, the uniaxial compressive strength is 3∼15.41 MPa, and the cohesion of severe sanding dolomite is 0.086∼0.17 MPa, the internal friction Angle is 16.17∼19.08°, the uniaxial compressive strength is 0.88–1.67 MPa. And the results were basically consistent with those of needle penetration test and dynamic rock mass tunnel test.
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spelling doaj-art-ec4e24b8b112450594a5cc4e61fadcf72025-08-20T02:41:23ZengFrontiers Media S.A.Frontiers in Earth Science2296-64632025-03-011310.3389/feart.2025.15223611522361Microstructure analysis and mechanical parameter estimation of sanding dolomiteFengnian Wang0Fengnian Wang1Fengnian Wang2Fengnian Wang3Zewei Li4Zewei Li5Yongxiang Shi6Yongxiang Shi7Xiaowen Gong8Yanjie Zhang9Shanxi Traffic Technology Research and Development Co., LTD., Taiyuan, ChinaState Key Laboratory for Tunnel Engineering, China University of Mining and Technology-Beijing, Beijing, ChinaSchool of Earth Sciences and Engineering, Hohai University, Nanjing, ChinaShanxi Intelligent Transportation Laboratory Co., LTD., Taiyuan, ChinaShanxi Traffic Technology Research and Development Co., LTD., Taiyuan, ChinaShanxi Intelligent Transportation Laboratory Co., LTD., Taiyuan, ChinaShanxi Traffic Technology Research and Development Co., LTD., Taiyuan, ChinaShanxi Intelligent Transportation Laboratory Co., LTD., Taiyuan, ChinaYunnan Dianzhong Water Diversion Engineering Co., LTD., Kunming, ChinaYunnan Dianzhong Water Diversion Engineering Co., LTD., Kunming, ChinaSanding dolomite strata are widely distributed in southwest China. The safety of the water diversion tunnel in Yuxi section of the Central Yunnan water diversion Project has been seriously threatened by the geological disasters such as the reduction of rock strength caused by dolomite sanding and tunnel sand inrush. In order to explore the mechanical characteristics and obtain the mechanical parameters of sanding dolomite quickly and accurately, this study relies on the Central Yunnan Water diversion Project to first established the classification standard of dolomite sanding grade. The pore structure, microscopic composition and morphological distribution of dolomite with different sanding degrees were studied by means of SEM scanning, EDS spectroscopy and CT scanning. At the same time, based on the field needle penetration test and the Hoek-Brown strength criterion considering the wave velocity and integrity coefficient of rock mass, a method for estimating the mechanical parameters of sanded dolomite was proposed, which was verified by NPI test and field adit test. The results showed that the sanding dolomite could be divided into four grades: slight sanding dolomite, moderate sanding dolomite, strong sanding dolomite and severe sanding dolomite. The higher the sanding grade, the higher the development degree of dolomite pores and the lower the mechanical strength. The action of groundwater will aggravate the dolomite dissolution sanding and lead to the aggravation of surrounding rock breakage. Based on the improved Hoek-Brown strength criterion, the cohesion of strong sanding dolomite is 0.34∼0.71 MPa, the internal friction Angle is 38.59∼50.96°, the uniaxial compressive strength is 3∼15.41 MPa, and the cohesion of severe sanding dolomite is 0.086∼0.17 MPa, the internal friction Angle is 16.17∼19.08°, the uniaxial compressive strength is 0.88–1.67 MPa. And the results were basically consistent with those of needle penetration test and dynamic rock mass tunnel test.https://www.frontiersin.org/articles/10.3389/feart.2025.1522361/fullSandingdolomitemicrostructuremechanical parametersestimatetest
spellingShingle Fengnian Wang
Fengnian Wang
Fengnian Wang
Fengnian Wang
Zewei Li
Zewei Li
Yongxiang Shi
Yongxiang Shi
Xiaowen Gong
Yanjie Zhang
Microstructure analysis and mechanical parameter estimation of sanding dolomite
Frontiers in Earth Science
Sanding
dolomite
microstructure
mechanical parameters
estimate
test
title Microstructure analysis and mechanical parameter estimation of sanding dolomite
title_full Microstructure analysis and mechanical parameter estimation of sanding dolomite
title_fullStr Microstructure analysis and mechanical parameter estimation of sanding dolomite
title_full_unstemmed Microstructure analysis and mechanical parameter estimation of sanding dolomite
title_short Microstructure analysis and mechanical parameter estimation of sanding dolomite
title_sort microstructure analysis and mechanical parameter estimation of sanding dolomite
topic Sanding
dolomite
microstructure
mechanical parameters
estimate
test
url https://www.frontiersin.org/articles/10.3389/feart.2025.1522361/full
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