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Zhichao Wang

Bio: Zhichao Wang is an academic researcher from Chang'an University. The author has contributed to research in topics: Loess & Geotechnical engineering. The author has an hindex of 4, co-authored 4 publications receiving 78 citations.

Papers
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Journal ArticleDOI
Junling Qiu1, Yongli Xie1, Haobo Fan1, Zhichao Wang1, Yuwei Zhang1 
TL;DR: Wang et al. as discussed by the authors conducted comprehensive centrifuge tests to obtain an in-depth knowledge of the mechanism of tunnel deformation induced by the twin-tunnelling, which can simulate and reproduce strictly the action process of twin-tunneling.
Abstract: A great concern for the safety of large cross-section tunnels, which are being or to be built in the loess strata of China, is attracted. Generally, loess is a multi-phase porous medium and develops complex stress and strain variation while executing a tunnel project. Another problem is that the soil surrounding both tunnel arches is subjected to a complex loading due to the double excavation. To obtain an in-depth knowledge of the mechanism of tunnel deformation induced by the twin-tunnelling, we conducted comprehensive centrifuge tests, which can simulate and reproduce strictly the action process of twin-tunnelling. Through the model tests, the response of twin-tunnelling on loess stratum deformation was obtained. The investigations showed that with the increase of tunnel spacing, the stratum deformation distribution near the vault changes from a single-peak V shape to a double-peak W shape. Additionally, the height of the stratum pressure arch effect increases significantly. The settlement of the preceding tunnel is slightly larger than that of the latter tunnel, and the twin-tunnelling effect gradually decreases with the increase of tunnel spacing. Through comparative analysis of the different combinations of tunnel spacing and tunnel interval, the interaction between two tunnels with different spacing and interval during tunnelling was investigated, further optimizing the reasonable tunnel spacing and construction steps, as well as providing reference for tunnel route selection in the loess strata.

52 citations

Journal ArticleDOI
Zhichao Wang1, Yongli Xie1, Junling Qiu1, Yuwei Zhang1, Haobo Fan1 
TL;DR: In this paper, a field soaking experiment was conducted on collapsible loess in western China, in which a soaking pool with diameter of 15'm was built and a pilot tunnel was excavated to investigate how the free face can affect the infiltration behaviors.
Abstract: In collapsible loess area, migration of soil moisture often causes the temporal discontinuity and spatial nonuniformity of collapsibility, which leads to great damage for infrastructures. Therefore, the research on water infiltration is the key to solving the problem of collapsibility. The aim of this paper is to investigate the spatiotemporal evolution of infiltration characteristics of collapsible loess. A field soaking experiment was conducted on collapsible loess in western China, in which a soaking pool with diameter of 15 m was built. Time-Domain-Reflectometry (TDR) system and soil sampling were employed to measure the water content within the depth of 12 m. Then the saturation isograms were drawn for visualization of the process of infiltration. Also, a pilot tunnel was excavated to investigate how the free face can affect the infiltration behaviors. The experimental results revealed the characteristics of infiltration in both horizontal and vertical directions. Moreover, the response of free face on infiltration behaviors was also found. These findings of research could provide the data for the infiltration laws of unsaturated loess and thereby provide the basis for integrated treatment of collapsible loess.

22 citations

Journal ArticleDOI
TL;DR: In this article, the ground fissure geology in Xi'an has been summarized and a series of countermeasures have been proposed to mitigate the possible damage of a utility tunnel, a case study, the construction of Kunming Road utility tunnel was referred to analyze the effectiveness of the adopted engineering countermeasures; the results have shown that the problems of structural damage and water seepage can be avoided; the maximum settlement of the surface is 1.35 cm, and the minimum settlement was 1.21 cm.
Abstract: There are 14 ground fissures covering the municipal area of Xi’an, which have threatened the construction of urban underground utility tunnel in Xi’an city. In this paper, the ground fissure geology in Xi’an has been summarized. When a utility tunnel is constructed in the ground fissure development area, some engineering problems such as damage of structure and pipeline, dual effect of earthquake and ground fissures, and water seepage may be encountered due to ground fissure disaster. To mitigate the possible damage of a utility tunnel, a series of countermeasures have been proposed. A case study, the construction of Kunming Road utility tunnel, was referred to analyze the effectiveness of the adopted engineering countermeasures; the results have shown that the problems of structural damage and water seepage can be avoided; the maximum settlement of the surface is 1.35 cm, and the minimum settlement is 1.21 cm, which proved that the movement of f3 ground fissure has been effectively controlled. This study can be helpful in developing utility tunnel in ground fissure area.

15 citations

Journal ArticleDOI
TL;DR: In this paper , the effect of longitudinal pressure bias on the stability of the SCCS arch in the dayoushan tunnel was analyzed. But the authors only focused on the out-of-plane stability.

14 citations

Journal ArticleDOI
TL;DR: The convergence-confinement method (CCM) as discussed by the authors is a widely used tunnel design method that can intuitively reflect the interaction between the surroundings and the support structure of the tunnel.
Abstract: The convergence–confinement method (CCM), a widely used tunnel design method, is an analysis approach that can intuitively reflect the interaction between the surroundings and the support ...

12 citations


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TL;DR: In this paper, the main available thermal insulation methods and their application are discussed and analyzed based on field investigations, and the optimization design method for tunnel heat insulation and anti-freezing by using geothermal energy and presented the challenges for future applications of ground-source heat pump (GSHP) system in tunnels.
Abstract: To cope with tunnel frost damage, studies on prevention methods are routinely conducted to improve environmental protection and energy saving. Based on field investigations, the main available thermal insulation methods and their application are discussed and analysed in this paper. The results show that passive measures, such as a thermal insulation layer or door, cannot completely avoid frost damage. Construction investment of the electric heat tracing (EHT) system is lower at the early stage, but a large investment in operation and pollution problems are needed in the later period. As renewable, clean and environmentally friendly primary energy, geothermal energy can realize energy-saving and emission-reduction. Furthermore, our research team proposed the optimization design method for tunnel heat insulation and anti-freezing by using geothermal energy and presented the challenges for future applications of the ground-source heat pump (GSHP) system in tunnels. The results regarding energy conservation from this review can provide useful technical support in design, operation and management of tunnels in cold regions.

107 citations

Journal ArticleDOI
TL;DR: In this paper, postconstruction settlement that occurs before a tunnel is in operation may significantly influence the tunnel's long-term stability, and the authors investigated such a tunnel, a three-l...
Abstract: Postconstruction settlement that occurs before a tunnel is in operation may significantly influence the tunnel’s long-term stability. The current study investigates such a tunnel, a three-l...

90 citations

Journal ArticleDOI
TL;DR: Wang et al. as discussed by the authors provided a case study on the Yingfeng tunnel (a tunnel constructed in soft rock consisting of a slate ground) based on a geological survey, indoor experiments and in situ monitoring.
Abstract: The Qingling–Bashan (QB) mountain region in southern Shaanxi mainly consists of strongly compressive zones from east to west, with tight folds and compressive fractures. There is a wide distribution of soft rocks of various types, such as phyllite and slate, accompanied by complex geological structures. Ironically, tunnel construction in these difficult grounds with complicated geological conditions embraces a high risk of extreme deformation due to various unpredictable reasons, which can frequently cause collapse and result in budget overruns during the construction period. Therefore, it is crucial to conduct effective countermeasures to eliminate or avoid such adverse impacts. This paper provides a case study on the “Yingfeng tunnel” (a tunnel constructed in soft rock consisting of a slate ground) based on a geological survey, indoor experiments and in situ monitoring. A successive rock mass deformation resulted in the tunnel lining seriously intruding into construction clearance and some other sections, even collapsing during the construction. The maximum displacement amount was 62.5 cm, while the maximum deformation speed reached as high as 34.18 mm/day. Additionally, to evaluate the construction impacts of tunnelling-induced geo-hazards, an investigation on extreme deformation was conducted. Considering the time-dependent features of the rock mass deformation, the constraint-convergence method was used to put forward applicable countermeasures in this paper. Finally, from the feedbacks of monitoring results, extreme deformation of the Yingfeng tunnel was effectively controlled.

86 citations

Journal ArticleDOI
TL;DR: A review of state-of-the-art work on mechanism, microstructure characteristic and physical mechanics mechanism of the seismic subsidence can be found in this paper, where the authors provide a comprehensive explanation, basics and earlier research performed on subsidence amount estimation and corresponding preventions of disasters have been presented briefly.
Abstract: Seismic subsidence of loess had been verified by microstructure characteristic, dynamic triaxial test and in situ simulation test using blasting vibration. It has gradually become a significant subject in the field of geotechnical earthquake engineering. Loess is widely distributed in China, which typically has a loose honeycomb-type meta-stable structure that is susceptible to a large reduction in total volume or subsidence upon ground motion. Seismic subsidence contributes to various problems to infrastructures that are constructed on loess. This paper provides a review of state-of-the-art work on mechanism, microstructure characteristic and physical mechanics mechanism of the seismic subsidence. Furthermore, the comprehensive explanation, basics and earlier research performed on subsidence amount estimation, seismic subsidence assessment and corresponding preventions of disasters have been presented briefly. The literature review shows that some significant problems, for example, appropriate theoretical basis, multi-variable coupling in assessment, physical processes, mechanical mechanism in estimation, and so on require constant research and development work to overcome the aforementioned factors. Specifically, research on quantitative relation between macro-mechanics and microstructure cannot proceed only from experimental parameters but should establish theoretical connection between them. Further study on seismic subsidence must be developed under the theory of unsaturated soil mechanics. In addition, research on chronological and spatial development law of large-scale seismic subsidence, prediction of subsidence value and anti-seismic analysis of underground structures can be conducted in future.

81 citations

Journal ArticleDOI
TL;DR: In this article, a simple method is proposed to predict the ground displacements caused by installing horizontal jet-grouting columns in soft ground, which is simplified as the expansion of a cylindrical cavity with a uniform radial stress applied at plastic-elastic interface in a half plane.
Abstract: During the horizontal jet grouting in soft ground, injection of large volumes of water and grout into the soil can lead to significant ground displacements. A simple method is proposed in this paper to predict the ground displacements caused by installing horizontal jet-grouting columns. The process of installing a horizontal column is simplified as the expansion of a cylindrical cavity with a uniform radial stress applied at plastic-elastic interface in a half plane. In this study, the analytical solution is adopted to calculate the deformation induced by the expansion of a cylindrical cavity. Considering the main jetting parameters (jetting pressure of the fluid, flow rate of the fluid, and withdrawal rate of the rod) and the soil properties (stiffness of the surrounding soil), an empirical equation to estimate the radius of plastic zone is developed. Two field tests are carried out in Shanghai, China, to verify the correctness and applicability of the proposed method. Comparisons between the predicted and measured values indicate that the proposed method can provide a reasonable prediction. The proposed simple method can be recommended as a useful tool for the design of ground improvement by means of horizontal jet grouting.

73 citations