Estimating strength parameters of Lower Gondwana coal measure rocks under dry and saturated conditions

Analysis of Rock Mechanical Characteristics and Establishment of an Evaluation System for Coal Measures in the Longtan Formation, Guizhou Province

“…Many researchers have tested the mechanical parameters of coal measure rocks, including the uniaxial compressive strength and tensile strength and investigated the relationships between the mechanical parameters of coal measure rocks, and between their mechanical parameters and acoustic wave velocity. − By comparing the uniaxial compressive strength and point load strength of coal measure rocks, disparities in the mechanical properties stemming from diverse lithologies have been revealed, and the failure modes and damage mechanisms within these rocks have been elucidated. , Furthermore, the influence of the occurrence environment (water, temperature, and other factors) on rock mechanical properties has attracted scholarly attention, and it was found that water can significantly diminish the strength parameters of coal measure rocks by absorbing and affecting the clay minerals in the rocks. Additionally, the seepage pressure substantially impacts the failure pattern and extent of damage within coal measure rocks under the action of water seepage. − Moreover, the increase in temperature exerts a discernible effect on the coal measure rock strength, presenting an initial increase followed by a subsequent decrease. Observations pertaining to the composition of the rock material and changes in the fine structure illustrate that augmented strength emanates from the thermal expansion of crystalline minerals, while the ongoing temperature rise leads to the decomposition of kaolinite and the thermal cracking of mineral grains, ultimately diminishing the rock strength. − Guizhou’s coal measure gas resources are primarily located in western Guizhou.…”