Anisotropic modeling of layered rocks incorporating planes of weakness and volumetric stress

Hu, Shengmin; Tan, Yunliang; Zhou, Hui; Ru, Wenkai; Ning, Jianguo; Wang, Jun; Huang, Dongmei; Li, Zhen

doi:10.1002/ese3.551

Cited by 47 publications

(29 citation statements)

References 44 publications

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“…The study area is located in the SW Taiwan Basin of the northeastern South China Sea, where submarine faults, bottom channels, and mud diapirs were developed [32]. Many studies have analyzed the hydraulic properties of rock fractures [33][34][35][36][37][38][39][40] and suggested that these fracture systems in strata are favorable pathway for fluid migration [41][42][43][44][45], but the fracture systems develop heterogeneously in natural environments, and the fracture prediction is quite difficult and needs more experimental investigations [46][47][48][49].…”

Section: Methodsmentioning

confidence: 99%

Effect of Sea-Level Change on Deep-Sea Sedimentary Records in the Northeastern South China Sea over the past 42 kyr

et al. 2020

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We integrated multiple geochemical analysis of a 13.75 m-long core 973-4 recovered from the northeastern South China Sea (SCS) to detect the response of deep-sea sediment archives to sea-level change spanning the last 42 kyr. The age-depth model based on AMS 14C dating, together with the sediment grain size, shows an occurrence of turbidity current at around 14 kyr, which was associated with submarine landslides caused by gas hydrate dissociation. A dominantly terrigenous sediment input was supplied from southwestern Taiwan rivers. By synthesizing environment-sensitive indexes, four distinct stages of paleoenvironmental evolutions were recognized throughout the studied interval. Well-oxygenated condition occurred during the stage I (42.4-31.8 kyr) with low sea-level stand below -80 m, accompanied by flat terrigenous input. The largest amounts of terrigenous sediment input occurred during the late phase of stage II (31.8-20.4 kyr) with the lowest sea-level stand below -120 m because of a short distance from paleo-Taiwan river estuaries to the core location. An occurrence of Ca-enriched turbidity current disturbed the original sediments during the stage III (20.4-13.9 kyr). The stepwise elevated sea-level stand resulted in an enclosed (semi-enclosed) system and contributed to a relatively low-oxygen environment in deep ocean during the stage IV (13.9 kyr—present). Temporal variations of TOC and CaCO3 display contrary pattern synchronously, indicating a decoupled relationship between organic carbon burial and carbonate productivity. Our results highlight that these sedimentary records as reflected in the paleoenvironmental changes in the northeastern SCS were mainly driven by sea-level fluctuations and later, since the mid-Holocene, the strengthening East Asian summer monsoon (EASM) overwhelmed the stable sea level in dominating the environmental changes.

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Section: Methodsmentioning

confidence: 99%

Effect of Sea-Level Change on Deep-Sea Sedimentary Records in the Northeastern South China Sea over the past 42 kyr

et al. 2020

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“…erefore, it is necessary to determine the geometric characteristics of cantilever beam structure, including its thickness, breaking length, and position on the coal wall. According to the geological conditions of 8211 working face, the thickness of cantilever beam is 13.5 m, and the breaking length can be solved by the following formula [42]:…”

Section: Geometric Characteristics Of Cantilever Beam Structurementioning

confidence: 99%

The Key Stratum Structure Morphology of Longwall Mechanized Top Coal Caving Mining in Extra‐Thick Coal Seams: A Typical Case Study

et al. 2020

Advances in Civil Engineering

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Longwall mechanized top coal caving mining (LMTCCM) in extra-thick coal seams has its own characteristics. The law of mining pressure and overlying strata failure height in extra-thick coal seams are much larger than those of medium-thick and thick coal seams. The key stratum structure morphology also has an important influence on the law of overlying strata movement and stability of surrounding rock. Based on the engineering geological conditions, this paper used the method of theoretical analysis and numerical simulation to study the key stratum structure morphology of LMTCCM in extra-thick coal seams. The results show that under the condition of LMTCCM in extra-thick coal seams, the key stratum forms the structure of low cantilever beam and high hinged rock beam. With the increase of coal seam thickness, the breaking position of cantilever beam is closer to the coal wall. Through theoretical calculation, it is obtained that the breaking length of cantilever beam is 31.5 m and the breaking position of cantilever beam is 15.4 m away from coal wall. With the increase of cycle, key strata will undergo the evolution law from the generation of longitudinal cracks to the hinged structure and then to the cantilever beam structure. The breakage of key strata will cause the expansion of longitudinal cracks and the overall synchronous movement of overlying strata. With the increase of coal seam thickness, the distribution of longitudinal cracks will gradually transfer from the upper part of goaf to the deep part of coal body in space and increase in quantity. This research is of great significance for improving the stability of overlying strata and ensuring the safe and efficient mining of extra-thick coal seams.

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“…Its height is an intuitive description of the shape of the water-flowing fracture zone. At present, field observation is the most accurate method to determine the DHOWFFZ, and the commonly used observation methods include underground double-end water plugging observation method, surface drilling flushing fluid consumption observation method, high-density resistivity method, and television imaging method [7][8][9]. However, the traditional empirical formula method is generally adopted in the prediction of DHOWFFZ currently in China because the complex field observation operation may affect the efficient production in coal mines.…”

Section: Introductionmentioning

confidence: 99%

Study on the Development Height of Overburden Water-Flowing Fracture Zone of the Working Face

Ding

Wang

et al. 2021

Geofluids

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Mining-induced fractures in underground coal mining face affect the stability of overburdens and provide preferential channels for water and material transfer in the underground environment. Therefore, to study the development of water-flowing fracture zones in overburdens of working face and goaf is of great significance for roof control, gas drainage, water resistance, disaster reduction, and efficient mining from the mining. In this study, a new method for predicting the development of overburden water-flowing fracture zone height (DHOWFFZ) was proposed based on the characteristics of overburden rock in No. 3 coal seam of Xin’an Coal Mine. First, the stope of No. 3 coal seam exhibits a rock stratum structure of mudstone and sandstone overlapping. Considering this characteristic, the overburden strata of No. 3 coal seam are divided into several “mudstone-sandstone” rock stratum groups. Furthermore, the ultimate tensile deformation of soft rock is greater than that of hard rock. It is proposed to judge the development degree of penetrating fracture in each rock stratum by adopting the elongation rate of mudstone intermediate layer. Meanwhile, the DHOWFFZ of “mudstone sandstone” composite rock stratum structure in the 3402 working face of No. 3 coal seam is calculated to be smaller than 43.1 m according to the actual situation. Finally, the DHOWFFZ in the 3402 working face was measured in the field, which verifies the rationality of the new DHOWFFZ prediction method. The research results provide new ideas for the prediction of DHOWFFZ and are helpful for future research in related fields.

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Anisotropic modeling of layered rocks incorporating planes of weakness and volumetric stress

Cited by 47 publications

References 44 publications

Effect of Sea-Level Change on Deep-Sea Sedimentary Records in the Northeastern South China Sea over the past 42 kyr

Effect of Sea-Level Change on Deep-Sea Sedimentary Records in the Northeastern South China Sea over the past 42 kyr

The Key Stratum Structure Morphology of Longwall Mechanized Top Coal Caving Mining in Extra‐Thick Coal Seams: A Typical Case Study

Study on the Development Height of Overburden Water-Flowing Fracture Zone of the Working Face

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