Papers by Keyword: Silty Mudstone

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Authors: Zhang Ming Li, Liang Liang Chen, Feng Wu, Ling Wan
Abstract: The shear strength characteristics of rock are very concerned in related underground construction. In this paper, in situ direct shear test for the weathered silty mudstone of the direct rock mass in a large section tunnel is carried out, the shear strength parameters are obtained, and some laws on the strength characteristics of this rock are got, such as that the displacement corresponds to the maximum shear stress under the given normal is decreased with increasing of normal loading number. This work provides a reference for the study of rock strength theory and its application.
Authors: Shi Ming Wan, Qi Hong Wu, You Lian Yang
Abstract: In order to research the weathering characteristics of Tertiary silty Mudstone along Chengnan Freeway, the experiment of the engineering characteristics, the weathering durability, the weathering speed to be done for the different weathering degree silty mudstone. The test result show that when the weathering degree of the rock mass deepen, the content of clay minerals in the rock mass is increase, the activity chemical composition in the rock mass is decrease relatively, the dry density of the silty mudstone is decrease, the total porosity and the water absorption of the silty mudstone is increase, the mechanical properties is weak, the rock mass is soften and collapse easily. The weathering speed of the rock mass with the relevant to the weathering degree and the exposed area of the rock mass.
Authors: Ji Hua Wang, Chen An, Zhou Yi
Abstract: To study the weathered characteristics of silty mudstone in Hunan province, china, mineral analysis, softening test, disintegrability test, and weathering rate test are used. The test results show that with the increasing of weathering degree, the content of clay minerals increase from 34.1% to 57.2%, the content of quartz decrease from 58.6% to 38.7%. The content increasing ratio of Fe2O3 and Al2O3 are 52% and 44% respectively, the content decreasing ratio of K2O is 52%. From lightly weathered rock to completely weathered rock, the decreasing ratio of dry density is 20%, the increasing ratio of water absorption is 40%, the increasing ratio of porosity is 190% nearly and the decreasing ratio of natural compressive strength is 84%. For strongly weathered silty mudstone, the softening coefficients of the first dry-wet cycle, the second cycle and the third cycle are 30%, 54% and 72% respectively. So when silty mudstone weathered further, the content of primary minerals decrease and the content of secondary minerals increase. The weak activity chemical composition increase and the strong activity chemical composition decrease. Weathering cause the mechanical properties of rock become worse. Repeated dry-wet cycle can accelerate the softening of rock. The larger the exposure area of rock is, the quicker the rock weathered.
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