Scholarlink

<p>Understanding how thermal cycles affect the shear behavior of dolomite is essential for assessing its mechanical stability under changing temperature conditions. This study examines the thermo-mechanical shear response of dolomite subjected to 0, 50, 100, and 500 heating and natural cooling cycles between 20 and 60 ℃. Recognizing that shear behavior is context-dependent, this study adopts a dual-methodological approach to broaden its scientific relevance. Two complementary methods; Short Core in Compression (SCC) as a direct shear test and Triaxial Compressive Stress (TCS) as an indirect shear test, were used to thoroughly assess shear strength variations caused by thermal cycling. Results showed that fresh, unweathered dolomite displayed distinct shear behavior. Both testing methods revealed a shear strength increase of about 12% to 82% with more thermal cycles, peaking around 350 cycles. After this point, shear strength decreased by roughly 3% to 5% following 500 cycles. The degree of improvement and decline varied depending on the normal stress applied during testing, which ranged from 0 to 96&#xa0;MPa. Similar trends were observed in the elastic modulus, shear modulus, failure envelopes, internal friction angle, and cohesion, highlighting the broader impact of thermal cycling on dolomite’s mechanical properties. SEM analysis revealed that the void size decreased due to the thermal expansion of dolomite grains as the number of cycles increased, up to around 352 cycles. Beyond this point, fatigue from repeated thermal cycles caused the voids to grow again. In addition, it was found that the shear strengths of SCC are 1.5 to 2.2 times higher than those of TCS, due to different failure mechanisms: SCC restricts failure to a specific plane, directly measuring cohesion and frictional resistance, whereas TCS allows failure along the weakest natural planes, resulting in lower shear strength values. These findings help deepen understanding of how thermal cycling affects rock strength and microstructure, and provide a robust framework for understanding thermal effects on dolomite shear strength across various engineering contexts.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Impact of heating and cooling cycles on dolomite’s shear behavior: a comparative analysis of direct and indirect shear methods

  • 期刊论文

  • 发表日期：

    2026年3月30日

查看全文
  • Mahmoud Alneasan,
  • Abdel Kareem Alzo’ubi

摘要

Understanding how thermal cycles affect the shear behavior of dolomite is essential for assessing its mechanical stability under changing temperature conditions. This study examines the thermo-mechanical shear response of dolomite subjected to 0, 50, 100, and 500 heating and natural cooling cycles between 20 and 60 ℃. Recognizing that shear behavior is context-dependent, this study adopts a dual-methodological approach to broaden its scientific relevance. Two complementary methods; Short Core in Compression (SCC) as a direct shear test and Triaxial Compressive Stress (TCS) as an indirect shear test, were used to thoroughly assess shear strength variations caused by thermal cycling. Results showed that fresh, unweathered dolomite displayed distinct shear behavior. Both testing methods revealed a shear strength increase of about 12% to 82% with more thermal cycles, peaking around 350 cycles. After this point, shear strength decreased by roughly 3% to 5% following 500 cycles. The degree of improvement and decline varied depending on the normal stress applied during testing, which ranged from 0 to 96 MPa. Similar trends were observed in the elastic modulus, shear modulus, failure envelopes, internal friction angle, and cohesion, highlighting the broader impact of thermal cycling on dolomite’s mechanical properties. SEM analysis revealed that the void size decreased due to the thermal expansion of dolomite grains as the number of cycles increased, up to around 352 cycles. Beyond this point, fatigue from repeated thermal cycles caused the voids to grow again. In addition, it was found that the shear strengths of SCC are 1.5 to 2.2 times higher than those of TCS, due to different failure mechanisms: SCC restricts failure to a specific plane, directly measuring cohesion and frictional resistance, whereas TCS allows failure along the weakest natural planes, resulting in lower shear strength values. These findings help deepen understanding of how thermal cycling affects rock strength and microstructure, and provide a robust framework for understanding thermal effects on dolomite shear strength across various engineering contexts.