Deep Underground Science and Engineering最新文献

{"title":"The mechanism of inward and outward expansion of multiscale dynamic permeability of coalbed methane at different temperatures","authors":"Zhiqiang Li,&nbsp;Xiaoqiang Hao,&nbsp;Yanwei Liu,&nbsp;Lin Li","doi":"10.1002/dug2.12036","DOIUrl":"https://doi.org/10.1002/dug2.12036","url":null,"abstract":"<p>The multiscale micro-nano pores in coal can result in the ultra-low permeability of coal, which restricts the efficiency of gas extraction. It is difficult for the conventional seepage-enhancement measures to affect the nanoscale pores within the coal matrix. Thermal stimulation can reach deep into the micro-nano pores within coal matrix to improve the permeability. Therefore, it is important to study the diffusivity and permeability of the multiscale micro-nano pores at different temperatures. In this study, the experiments of diffusion-seepage measured by the methods of GRI (Gas Research Institution) and steady-state were conducted using a cylindrical coal at different temperatures and pressures. The experimental results show that the apparent diffusion coefficient of cylindrical coal is not constant but variable dynamically; and the classical diffusion model fails to describe the full-time process of gas flow accurately. On this basis, a model of multiscale dynamic apparent diffusion-seepage that can accurately describe the full-time flow process was proposed. As is observed, the apparent permeability attenuates dynamically with time without stress loading, and the initial apparent permeability and the attenuation coefficient increase monotonically with the rise of temperature. Under the stress constraint, the steady-state permeability increases after a decrease as the temperature rises, displaying a “U-shaped” pattern. Without stress constraint, the increasing temperature causes the exterior multiscale pores to expand outward by different degrees so as to increase permeability, while the interior micro-nano pores show three inward and outward expansion mechanisms. Under stress constraint, at low temperature and high effective stress, the increasing temperature causes pores to expand inward and the permeability decreases accordingly. When temperature continues to increase, coal expands outward because the effective stress is counteracted by the thermal stress, leading to an increase in permeability. This study is of significance for thermal gas extraction engineering.</p>","PeriodicalId":100363,"journal":{"name":"Deep Underground Science and Engineering","volume":"2 1","pages":"88-101"},"PeriodicalIF":0.0,"publicationDate":"2023-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dug2.12036","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50153674","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Editorial highlights","authors":"Qingbin Meng,&nbsp;Heping Xie,&nbsp;ChunFai Leung,&nbsp;Xiaozhao Li,&nbsp;Jianguo Wang","doi":"10.1002/dug2.12038","DOIUrl":"https://doi.org/10.1002/dug2.12038","url":null,"abstract":"<p>This paper by the team of Hongpu Kang, academician of the Chinese Academy of Engineering, reviews comprehensively the theories and technologies of grouting reinforcement of fractured rocks surrounding the deep roadway. It also profiles their outstanding contributions to the theory, technology, and practice in this field. The methods and processes described in this paper are highly helpful and forward-looking. The future development directions on deep grouting theory and technology are outlined. The cases studied in the paper can be important references for researchers and engineers to guide their design, installation, and effect evaluation on grouting reinforcement.</p>","PeriodicalId":100363,"journal":{"name":"Deep Underground Science and Engineering","volume":"2 1","pages":"1"},"PeriodicalIF":0.0,"publicationDate":"2023-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dug2.12038","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50152781","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental study on 3D internal penny-shaped crack propagation in brittle materials under uniaxial compression","authors":"Jiyun Xu,&nbsp;Hanzhang Li,&nbsp;Haijun Wang,&nbsp;Lei Tang","doi":"10.1002/dug2.12037","DOIUrl":"https://doi.org/10.1002/dug2.12037","url":null,"abstract":"<p>Fractures are widely present in geomaterials of civil engineering and deep underground engineering. Given that geomaterials are usually brittle, the fractures can significantly affect the evaluation of underground engineering construction safety and the early warning of rock failure. However, the crack initiation and propagation in brittle materials under composite loading remain unknown so far. In this study, a three-dimensional internal laser-engraved cracking technique was applied to produce internal cracks without causing damage to the surfaces. The uniaxial compression tests were performed on a brittle material with internal cracks to investigate the propagation of these internal cracks at different dip angles under compression and shear. The test results show that the wing crack propagation mainly occurs in the specimen with an inclined internal crack, which is a mixed-Mode I–II–III fracture; in contrast, Mode I fracture is present in the specimen with a vertical internal crack. The fractography characteristics of Mode III fracture display a lance-like pattern. The fracture mechanism in the brittle material under compression is that the internal wing cracks propagate to the ends of the whole sample and cause the final failure. The initial deflection angle of the wing crack is determined by the participation ratio of stress intensity factors <i>K</i>_II to <i>K</i>_I at the tip of the internal crack.</p>","PeriodicalId":100363,"journal":{"name":"Deep Underground Science and Engineering","volume":"2 1","pages":"37-51"},"PeriodicalIF":0.0,"publicationDate":"2023-03-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dug2.12037","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50150810","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Experimental study on the irreversible displacement evolution and energy dissipation characteristics of disturbance instability of regular joints","authors":"Jianan Yang,&nbsp;Pengxian Fan,&nbsp;Mingyang Wang,&nbsp;Jie Li,&nbsp;Lu Dong","doi":"10.1002/dug2.12035","DOIUrl":"https://doi.org/10.1002/dug2.12035","url":null,"abstract":"<p>To investigate the disturbance-induced shear instability mechanism of structural catastrophe in the deep rock mass, MTS 815 material testing machine was used to carry out quasi-static loading tests and disturbance shear tests on symmetrical regular dentate joints of two materials at three undulation angles under specific initial static stress, disturbance frequency, and peak value. The test results indicate that: (i) the total ultimate instability displacement is only related to the intrinsic properties of the joints but not to the initial static stress and disturbance parameters; (ii) the cumulative irreversible displacement required for the disturbance instability conforms to the logistic inverse function relationship with the number of disturbances, displaying the variation trend of “rapid increase in the front, stable in the middle, and sudden increase in the rear”; (iii) the accumulation of plastic deformation energy is consistent with the evolution law of irreversible displacement of joints and the overall proportion of hysteretic energy is not large; (iv) the dissipated energy required for the instability of each group of joints is basically the same under various disturbance conditions, and this energy is mainly controlled by the initial shear stress and has no connection with the disturbance parameters. The stability of the total disturbance deformation and the disturbance energy law of the joints revealed in the tests provide data support for reasonably determining the disturbance instability criterion of joints.</p>","PeriodicalId":100363,"journal":{"name":"Deep Underground Science and Engineering","volume":"2 1","pages":"20-36"},"PeriodicalIF":0.0,"publicationDate":"2023-03-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dug2.12035","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50132024","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Triaxial creep damage characteristics of sandstone under high crustal stress and its constitutive model for engineering application","authors":"Dongxu Chen,&nbsp;Laigui Wang,&nbsp;Pierre Darry Versaillot,&nbsp;Chuang Sun","doi":"10.1002/dug2.12033","DOIUrl":"https://doi.org/10.1002/dug2.12033","url":null,"abstract":"<p>The creep characteristics of rock under high crustal stress are of important influence on the long-term stability of deep rock engineering. To study the creep characteristics and engineering application of sandstone under high crustal stress, this study constructed nonlinear creep damage (NCD) constitutive mode based on the triaxial graded loading‒unloading creep test of sandstone in the Yuezhishan Tunnel. A numerical NCD constitutive model and a breakable lining (BL) model were developed based on FLAC^3D and then applied to the stability analysis of the Yuezhishan Tunnel. Based on the creep test results of sandstone, a power function of creep rate and stress level was constructed, by which the long-term strength was solved. The results show that the long-term strength of the red sandstone based on the related function of the steady-state creep rate and stress level is close to the measured stress value in engineering. The NCD model considering damage factors reflects the instantaneous and viscoelastic plasticity deformation characteristics of the red sandstone. The numerical NCD constitutive model and the BL model can reflect surrounding rock deformation characteristics and lining failure characteristics in practical engineering. The research results provide theoretical references for long-term stability analysis of rock engineering and the deformation control of surrounding rock under high crustal stress.</p>","PeriodicalId":100363,"journal":{"name":"Deep Underground Science and Engineering","volume":"2 3","pages":"262-273"},"PeriodicalIF":0.0,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dug2.12033","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50118435","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical investigation on the spewing mechanism of earth pressure balance shield in a high-pressure water-rich sand stratum","authors":"Zhiyong Yang,&nbsp;Weiqiang Qi,&nbsp;Yanjie Ding,&nbsp;Yusheng Jiang,&nbsp;Xinkang Yang,&nbsp;Xing Yang,&nbsp;Xiaokang Shao","doi":"10.1002/dug2.12032","DOIUrl":"https://doi.org/10.1002/dug2.12032","url":null,"abstract":"<p>The spewing of a screw conveyor easily occurs from the earth pressure balance (called EPB) shield in a water-rich sand stratum. This may lead to the collapse of the tunnel face and even serious subsidence of the ground surface. To understand the spewing mechanism of the shield screw conveyor and explore the critical hydraulic condition of soil spewing in a shield–soil chamber, a simplified theoretical model for the spewing of the screw conveyor was developed based on the equation of groundwater flow in the screw conveyor under turbulent state. Thus, coupling Darcy's law with Brinkman's equation, this model was implemented within the COMSOL Multiphysics framework. The underground water flow in the shield screw conveyor was simulated so as to obtain its velocity and flow rate. Numerical simulations show that the water pressure distribution is concentrated in the lower part of the soil chamber after the groundwater enters the soil chamber. When the groundwater enters the screw conveyor, its pressure gradually decreases along the direction of the screw conveyor. When the water flow reaches the stratum–shield interface, the flow velocity changes markedly: first increases and concentrates at the entrance of the lower soil chamber, plummets and stabilizes gradually, and increases again at the exit. The soil chamber and screw conveyor are significantly depressurized. It is also found that the soil permeability coefficient can be reduced to <i>k</i> &lt; 2.6 × 10⁻⁴ cm/s through appropriate soil improvement, which can effectively prevent the occurrence of spewing disasters.</p>","PeriodicalId":100363,"journal":{"name":"Deep Underground Science and Engineering","volume":"2 1","pages":"74-87"},"PeriodicalIF":0.0,"publicationDate":"2023-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dug2.12032","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50145487","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Development of urban underground space in coastal cities in China: A review","authors":"Peng Yu,&nbsp;Honghua Liu,&nbsp;Zhongsheng Wang,&nbsp;Jiani Fu,&nbsp;Hui Zhang,&nbsp;Jia Wang,&nbsp;Qi Yang","doi":"10.1002/dug2.12034","DOIUrl":"https://doi.org/10.1002/dug2.12034","url":null,"abstract":"<p>The development of urban underground space is a critical way to alleviate the lack of urban resources, and improve environmental conditions as well as residents' quality of life, which has important practical significance. As the most densely populated and economically developed areas, coastal cities face many challenges in underground space development owing to their unique environmental geological conditions. This study examined the current situation of underground space development, academic research, technology application, evaluation methods, planning, and legislation in coastal cities in China. On this basis, it analyzed the future development trends, and presented reasonable suggestions for the critical scientific and technical problems faced by the development of underground space in coastal cities. The key suggestions are as follows: it is necessary to define and clarify the critical geological issues, distributions, and hazards that affect underground space development and major engineering construction in coastal cities; the land-sea integrated detection technology for sea crossing bridges and submarine tunnels needs to be studied; in evaluating the suitability of underground space in coastal cities, the land and sea area evaluation factors should be integrated; and the evaluation system of land-sea integration needs to be established.</p>","PeriodicalId":100363,"journal":{"name":"Deep Underground Science and Engineering","volume":"2 2","pages":"148-172"},"PeriodicalIF":0.0,"publicationDate":"2023-02-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dug2.12034","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50139770","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Research on in situ stress inversion of deep-buried tunnel based on pressure/tension axis mechanism and geological structure","authors":"Guanfu Chen,&nbsp;Xiaoli Liu,&nbsp;Danqing Song","doi":"10.1002/dug2.12025","DOIUrl":"https://doi.org/10.1002/dug2.12025","url":null,"abstract":"<p>The investigation of the in situ stress distribution has always been a key condition for engineering design of deep tunnels and analysis of surrounding rock stability. In this paper, a comprehensive judgment method coupled with pressure/tension (P/T) axis mechanism and geological structure is proposed to invert the in situ stress in the Duoxiongla tunnel in Tibet. In the process of TBM tunnel excavation, 3887 groups of microseismic events were collected by means of microseismic monitoring technology. By studying the temporal and spatial distribution of 3887 groups of microseismic events, 42 groups of microseismic data were selected for in situ stress inversion. Then the focal mechanisms of 42 groups of microseisms were inverted. Combined with the analysis of the previous geological survey, the inversion results of the in situ stress were analyzed. According to the focal mechanism of the tunnel area, the linear in situ stress inversion method was used to invert the in situ stress in the source area. Finally, according to the PTGS (pressure/tension axis mechanism and geological structure) comprehensive judgment method proposed in this paper, the in situ stress of the tunnel microseismic region was determined. The results show that there are mainly three groups of fissures and joint surfaces in the tunnel area, and the in situ stress is dominated by the horizontal tectonic stress; the main driving force of the rupture surface in the excavation process of Duoxiongla tunnel is the horizontal tectonic stress; the distribution of the maximum and minimum principal stress obtained by the inversion is consistent with the distribution of the P/T axis; combined with the linear in situ stress inversion method and the comprehensive judgment of PTGS, the azimuth and dip angles of the three principal stresses are finally determined as N90.71°E, 4.06°, N5.35°W, 3.06°, and N8.10W, 85.32°, respectively. The study verifies the feasibility of microseismic inversion of in situ stress.</p>","PeriodicalId":100363,"journal":{"name":"Deep Underground Science and Engineering","volume":"2 1","pages":"61-73"},"PeriodicalIF":0.0,"publicationDate":"2023-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dug2.12025","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50133851","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Energy-based analysis of seismic damage mechanism of multi-anchor piles in tunnel crossing landslide area","authors":"Hong Wei,&nbsp;Honggang Wu,&nbsp;Guojun Ren,&nbsp;Lin Tang,&nbsp;Kang Feng","doi":"10.1002/dug2.12030","DOIUrl":"https://doi.org/10.1002/dug2.12030","url":null,"abstract":"<p>To study the damage mechanism of multi-anchor piles in tunnel crossing landslide area under earthquake, the damping performance of multi-anchor piles was discussed. The energy dissipation springs were used as the optimization device of the anchor head to carry out the shaking table comparison test on the reinforced slope. The Hilbert spectrum and Hilbert marginal spectrum were proposed to analyze the seismic damage mechanism of the multi-anchor piles, and the peak Fourier spectrum amplitude (PFSA) was used to verify the effectiveness of the method. The results show that the seismic energy is concentrated in the high-frequency component (30–40 Hz) of the Hilbert spectrum and the low-frequency component (12–30 Hz) of the marginal spectrum. This indicates that they can be combined with the distribution law of the PFSA to identify the overall and local dynamic responses of the multi-anchored piles, respectively. The stretchable deformation of the energy-dissipation springs improves the coordination of the multi-anchor piles, resulting in better pile integrity. The damage mechanism of the multi-anchor piles is elucidated based on the energy method: local damage at the top and middle areas of the multi-anchor piles is mainly caused by the low-frequency component (12–30 Hz) of the marginal spectrum under the action of 0.15<i>g</i> and 0.20<i>g</i> seismic intensities. As the seismic intensity increases to 0.30<i>g</i>, the dynamic response of the slope is further amplified by the high-frequency component (30–40 Hz) of the Hilbert energy spectrum, which leads to the overall damage of the multi-anchor piles.</p>","PeriodicalId":100363,"journal":{"name":"Deep Underground Science and Engineering","volume":"2 3","pages":"245-261"},"PeriodicalIF":0.0,"publicationDate":"2023-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dug2.12030","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50133840","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Correction to: Wear mechanism and life prediction of the ripper in a 9-m-diameter shield machine tunneling project of the Beijing new airport line in a sand-pebble stratum","authors":"","doi":"10.1002/dug2.12031","DOIUrl":"https://doi.org/10.1002/dug2.12031","url":null,"abstract":"<p>Jiang H, Zhu J, Zhang X, Zhang J, Li H, Meng L. Wear mechanism and life prediction of the ripper in a 9-m-diameter shield machine tunneling project of the Beijing new airport line in a sand-pebble stratum. <i>Deep Undergr Sci Eng</i>. 2022;1:65-76. doi:10.1002/dug2.12010.</p><p>There is an error in Figure 10. The corrected Figure 10 is shown below.</p><p>We apologize for this error.</p>","PeriodicalId":100363,"journal":{"name":"Deep Underground Science and Engineering","volume":"2 3","pages":"274"},"PeriodicalIF":0.0,"publicationDate":"2023-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/dug2.12031","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"50149913","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}