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Stability evaluation and protection of a highly weathered mudstone slope in Yunnan
Published in Mohd Johari Mohd Yusof, Junwen Zhang, Advances in Civil Engineering: Structural Seismic Resistance, Monitoring and Detection, 2023
The stability of intense weathering slopes is a common problem in highway engineering. Mudstone is a sedimentary rock that comprises solidified mud and clay; its structure is similar to shale, but it is more durable. It also has a poor degree of consolidation with recrystallization that is not obvious, which leads to its poor weathering resistance and a tendency to soften and disintegrate upon contact with water. Many highly weathered mudstone slopes collapsed during construction in the past, posing considerable threat to the safety of human life and property, as well as the normal operation of roads, also resulting in serious soil erosion. In this paper, the shear strength reduction finite element method is used to calculate the safety coefficient of a highly weathered mudstone high slope of an expressway, and the comprehensive protection measures for the slope are introduced, which can be used as references for other similar slope projects.
Underground hard rock (metal/non-metal) mining
Published in A.J.S. (Sam) Spearing, Liqiang Ma, Cong-An Ma, Mine Design, Planning and Sustainable Exploitation in the Digital Age, 2023
A.J.S. (Sam) Spearing, Liqiang Ma, Cong-An Ma
The challenges in weak rock are also significant and the following should be considered: These excavations are difficult to analyze as failure is typically progressive and weathering can also be a factor.Even relatively low stresses can cause failures.Typical rock types include mudstones, siltstones, tuffs and some especially laminated shales.Deformation monitoring is essential and shotcrete, cast concrete and arches are commonly used.
Drilling and Rock Mechanics
Published in C.P. Chugh, Ken Steele, V.M. Sharma, Design Criteria for Drill Rigs: Equipment and Drilling Techniques, 2020
C.P. Chugh, Ken Steele, V.M. Sharma
Porosity is a measure of the voids in rock and their capacity for holding water; permeability, the capacity of rocks to let water pass through, is a measure of those voids which are of sufficient size and are in communication. Mud has a high level of porosity that diminishes during its conversion first to clay and later to mudstone or shale. Even then it has a certain porosity but because of the fineness of the clay particles and, therefore, the minute dimensions of the voids, it is impermeable to water. Permeability is thus a measure both of particulate size and degree of packing and can be defined as hydraulic conductivity.
Multitechnique approach for characterizing the hydrogeology of aquifer systems: application to the Mauricie region of Québec, Canada
Published in Canadian Water Resources Journal / Revue canadienne des ressources hydriques, 2023
Yan Lévesque, Julien Walter, Lamine Boumaiza, Mélanie Lambert, Anouck Ferroud, Romain Chesnaux
The geology of the eastern Mauricie is characterized by rock outcrops and a variety of Quaternary surface deposits (Gadd and Karrow 1960; Gadd and Goldthwait 1971; Occhietti 2007; Occhietti et al. 2007; Lasalle and Chagnon 1968). The main lithological units of the region are (1) the crystalline rocks of the Grenville Province of the Canadian Shield (i.e. high-grade igneous and intrusive metamorphic rocks: metasedimentary, metavolcanic, felsic intrusive; Rivers, van Gool, and Connelly 1993), mainly found in the highlands and underneath Piedmont, and (2) the stratified Paleozoic sedimentary rocks of the St Lawrence Platform, dominating the lowlands. Most of the platform is buried under the surface sediments and marine clay related to the incursion of the Champlain Sea during the last deglaciation. The rocks of the St Lawrence Platform are composed mainly of Ordovician carbonate (Trenton Group) but also include shale, mudstone (Utica and Lorraine groups), and Ordovician sandstone (Black River Group) deposited in a marine environment (Légaré-Couture et al. 2018; Globensky 1987; Occhietti 2011; Douglas et al. 1970; Occhietti 1980; Simard, Occhietti, and Robert 2005). Mudstone and shale are sedimentary rocks of very fine grain size and therefore have low permeability. Moreover, the water that passes into the shale is of poor drinking quality because these rocks often contain natural gas and oil (Légaré-Couture et al. 2018; Globensky 1987).
Research progress and prospects of deep water episodically deposited mudstones
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2020
Siqi Wang, Jianguo Zhang, Changsheng Li, Luyao Feng, Zaixing Jiang
Mudstones are generally defined as rocks composed of fine-grained minerals (<62.5 μm) (Jiang, Liang, and Wu 2013), and they account for two-thirds of the whole sedimentary rocks (Potter, Maynard, and Depetris 2005). Traditionally, mudstones are speculated to result from slow deposition of suspended materials in the still water environment (Katz 2005). However, with advancement in research, this understanding has been confronted with enormous challenges (Macquaker and Bohacs 2007). Specifically, it has been found in the water tank experiments that the floc formed by aggregation of fine particles can also be deposited under the hydrodynamic force that is sufficient to carry sand particles (Schieber, Southard, and Thaisen 2007). Moreover, a large quantity of mudstone deposited under the action of episodic water flow has been reported in more than ten basins (Polonia, Vaiani, and Lange 2016), and much attention is aroused on the role of episodic deposition in the formation of mudstones.
Influence of sedimentary environment on the shale gas reservoir of Sahai formation in Fuxin Basin, northeast China
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2019
Daye Chen, Jinchuan Zhang, Bo Lan, Xiaoming Wang, Zhen Wang
Sedimentary environments play an important role in influencing the quality and distribution of hydrocarbon sources, reservoirs, and cap rocks. In addition, sedimentary environments impact the shale reservoir through organic carbon content, rock mineral components, thickness, and distribution (Bjørlykke 2014; Li et al. 2016). Dark organic-rich mudstone or shale mainly developed in environments that feature low energy and anoxic environments such as swamps, lagoons, shelfs, continental slopes, underfilled basins, and deep lake environments (Bjørlykke 2014; Friedman and Sanders 1978; Potter, Maynard, and Depetris 2005). In north China, numerous lacustrine basins can be found, which have been proved to offer an enormous potential for shale gas and oil extraction; therefore, discovering shale reservoirs under the influence of sedimentary environments has significance for shale gas exploration. However, investigations of relationships between sedimentary environments and the faulted lacustrine shale reservoir of continental faulted lacustrine have been rarely reported. The Fuxin Basin is a typical continental faulted lacustrine basin in northeast China and organic-rich shale developed in the third and fourth members of the lower cretaceous Sahai formation. In recent years, shale gas exploration has made significant progress in Fuxin Basin, and the gas testing of Liuye-1 well, in particular, has yielded high industrial gas flow. This study uses the thirrd and fourth members of the Sahai formation of Fuxin Basin as the case study to investigate the influence of sedimentary environments on shale reservoirs and will thus lay a solid foundation for subsequent exploration of continental shale gas.