Experimental Study on the Bearing Mechanisms of Rock-socketed Piles in Soft Rock Based on Micro X-ray CT Analysis

Xu, Jiang; Haque, Asadul; Gong, Weiming; Gamage, Ranjith Pathegama; Dai, Guoliang; Zhang, Qi; Xu, Feng

doi:10.1007/s00603-020-02121-3

Cited by 55 publications

(38 citation statements)

References 43 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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“…Since the inorganic and organic pores were found in shales, lots of equipment has been used to study the pore structure features [5,8,12,18,19]. The morphology of shale pores could be visualized via imaging equipment, like field emission scanning electron microscopy and computerized tomography [20][21][22]. Using intrusion tests (for example, pressure-controlled mercury intrusion) and nonintrusion experiments (for instance, nuclear magnetic resonance), the pore network distributions could be quantitatively gained, and the pore structure-related parameters, such as average pore radius, pore volumes, and surface areas can be calculated [23][24][25].…”

Section: Introductionmentioning

confidence: 99%

Characterization of Shale Pore Structure by Multitechnique Combination and Multifractal Analysis and Its Significance

et al. 2020

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Understanding pore structure would enable us to obtain a deeper insight into the fluid mechanism in porous media. In this research, multifractal analysis by various experiments is employed to analyze the pore structure and heterogeneity characterization in the source rock in Ordos Basin, China. For this purpose, imaging apparatus, intrusion tests, and nonintrusion methods have been used. The results show that the objective shale reservoir contains complex pore network, and minor pores dominant the pore system. Both intrusion and nonintrusion methods detected pore size distributions show multifractal nature, while the former one demonstrates more heterogeneous features. The pore size distributions acquired by low temperature adsorption and nuclear magnetic resonance have relatively good consistence, indicating that similar pore network detection method may share the same mechanism, and the full-ranged pore size distributions need to be acquired by multitechniques. Chlorite has an obvious impact on the heterogeneity of pore structure in narrow pore size range, while illite and I/S mixed layer influence that in wide range. Kerogen index is the fundamental indicators of geochemical parameters. With the decrease of averaged small and middle/large pore radius, the heterogeneity of pore structures increase in narrow and wide ranges, respectively. This work employed a comprehensive methodology based on multitechniques and helps to explore how pore networks affect reservoir quality in shale reservoirs.

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“…In a study conducted by the Commonwealth Scientific and Industrial Research Organization (CSIRO), the gas flow model and well deformation characteristics during surface well gas extraction were investigated. Goaf gas migration in the context of vertical well gas extraction was investigated by means of numerical calculations [22,23]. In addition, a well spacing principle was proposed from the perspective of gas extraction efficiency.…”

Section: Introductionmentioning

confidence: 99%

Three‐Dimensional Physical Similarity Simulation of the Deformation and Failure of a Gas Extraction Surface Well in a Mining Area

Sun

Wen

et al. 2020

Advances in Civil Engineering

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Surface well deformation and failure in a mining area are a key issue challenging the surface well gas extraction technique. To provide information for the design of gas extraction surface wells in mining areas, the deformation and failure of surface wells with different materials under the influence of mining-induced rock movement were analyzed based on a three-dimensional physical similarity simulation and key strata theory. The research findings reveal that the fractures in the overlying strata had an elliptic-parabolic shape. The stope center was the highest point in the fracture zone. Horizontal shear deformation was most likely to occur in the thick strata (horizontal shear deformation could be larger if they were key strata) with large strength and stiffness near the intersection between the fracture surface of the overlying strata and the surface well. Due to the shear force and bending moment of the key strata, the surface well deformed into an S-shape. In addition, the surface well was vulnerable to shear deformation in the key strata. The surface well deformation did not weaken from bottom to top due to rock movement. Instead, it was subject to the influence of the rupture strength of the key strata. The surface well above the key strata was prone to tensile strain-compressive strain transition. In contrast, an abrupt change in the compressive strain occurred in the surface well below the key strata where tensile failure may occur. Moreover, a mechanical model of the surface well during the movement of the key strata was established according to the characteristics of the surface well deformation. The test results provide important information on the design optimization of surface wells and high-risk area protection in mining areas.

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Experimental Study on the Bearing Mechanisms of Rock-socketed Piles in Soft Rock Based on Micro X-ray CT Analysis

Cited by 55 publications

References 43 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

Characterization of Shale Pore Structure by Multitechnique Combination and Multifractal Analysis and Its Significance

Three‐Dimensional Physical Similarity Simulation of the Deformation and Failure of a Gas Extraction Surface Well in a Mining Area

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