|
|
|
题名
|
作者
|
年代
|
出处
|
被引量
|
| 1 | Excavation-induced deep hard rock fracturing:Methodology and applications显示文摘To analyze and predict the mechanical behaviors of deep hard rocks,some key issues concerning rock fracturing mechanics for deep hard rock excavations are discussed.First,a series of apparatuses and methods have been developed to test the mechanical properties and fracturing behaviors of hard rocks under high true triaxial stress paths.Evolution mechanisms of stress-induced disasters in deep hard rock excavations,such as spalling,deep cracking,massive roof collapse,large deformation and rockbursts,have been recognized.The analytical theory for the fracturing process of hard rock masses,including the three-dimensional failure criterion,stress-induced mechanical model,fracturing degree index,energy release index and numerical method,has been established.The cracking-restraint method is developed for mitigating or controlling rock spalling,deep cracking and massive collapse of deep hard rocks.An energy-controlled method is also proposed for the prevention of rockbursts.Finally,two typical cases are used to illustrate the application of the proposed methodology in the Baihetan caverns and Bayu tunnels of China. | Xia-Ting Feng Cheng-Xiang Yang Rui Kong Jun Zhao Yangyi Zhou Zhibin Yao Lei Hu | 2022 | Journal of Rock Mechanics and Geotechnical Engineering2022，14，1： | 4 |
| 2 | A local homogenization approach for simulating the reinforcement effect of the fully grouted bolt in deep underground openings显示文摘Fully grouted bolts are a key component of the support system for underground openings.Although considerable effort has been made in the simulation of the reinforcement effect of the fully grouted bolts on the rock masses surrounding underground openings,most of the work has limited significance since the structural element approach is used.This study proposes a local homogenization approach(L-H approach)that integrates elastoplastic mechanics,composite mechanics,and analytical approaches with numerical simulation to effectively simulate the reinforcement effect of the fully grouted bolt on deep surrounding rock masses.In the L-H approach,the representative volume of bolted rock mass(RVBRM)with a fully grouted bolt is established based on the original mesh model utilized in the rockbolt element approach.The RVBRM is a regular quadrangular prism with a cross-sectional size equal to the bolt spacing and a length equal to the bolt length.The RVBRM is homogenized by the L-H approach from a unidirectional bolt-reinforced composite into a homogeneous transversely isotropic medium whose mechanical properties are described by a new transversely isotropic elastoplastic model.The L-H parameters for the RVBRM are obtained using analytical approaches,composite mechanics,and known parameters of the rock mass and bolt.Using the L-H approach,the reinforcement effect of the fully grouted bolt on the bolted rock specimen and the surrounding rock mass in Jinping II Diversion Tunnel#2 with a depth greater than 2000 m is simulated.The results show that the predictions of the L-H approach are more in agreement with the physical model results of bolted rock specimen and provide a more realistic response of the bolted surrounding rock mass.The L-H approach demonstrates that fully grouted bolts with common bolt spacings and diameters substantially enhance the elastic modulus,shear strength,and tensile strength of the rock mass in the direction of the bolt axis. | Dingping Xu Xiuyang Liu Quan Jiang Shaojun Li Yangyi Zhou Shili Qiu Fei Yan Hong Zheng Xiang Huang | 2022 | International Journal of Mining Science and Technology2022，32，2： | 3 |
| 3 | Experimental investigation on fracturing process of marble under biaxial compression显示文摘In this study,servo-controlled biaxial compression tests were conducted on marble specimens to investigate their failure characteristics and fracturing process.The complete stressestrain curves were obtained,and the three-dimensional(3D)features of the failure surfaces were acquired by 3D laser scanning.Acoustic emission(AE)monitoring and moment tensor(MT)analysis were used in combination to better understand the fracturing mechanism of marble under biaxial compression.It was noted that a type of 3D stepwise cracking behaviour occurred on the fracturing surfaces of the examined specimens.The stress dropped multiple times,and a repeated fracturing mode corresponding to the repeated stress drops in the post-peak regime was observed.Three substages,i.e.stress stabilisation,stress decrease and stress increase,were identified for a single fracturing mode.Then quantitative and statistical analyses of the fracturing process at each substage were discussed.Based on the testing results,it was found that at the stress stabilisation substage,the proportion of mixed-mode fractures increased.At the stress decrease substage,the proportion of mixed-mode fractures decreased,and the tensile or shear fractures increased.At the stress increase substage,the proportion of mixed-mode or tensile fractures decreased,and the shear fractures increased.Finally,a conceptual model for the stepwise crack formation was proposed. | Zhaofeng Wang Xia-Ting Feng Chengxiang Yang Yangyi Zhou Hong Xu Qiang Han Yaohui Gao | 2020 | Journal of Rock Mechanics and Geotechnical Engineering2020，12，5： | 3 |
| 4 | Effect of Lamb Age and in vitro Culture System of Oocytes on JIVET Technology显示文摘[Objectives] This study was conducted to investigate the effects of lamb age and in vitro culture system of oocytes on the results of juvenile in vitro embryo transfer( JIVET). [Methods]Ten Dorper × small-tailed Han lambs aged 5 to 10 weeks were induced to superovulate via i. p. injection of pregnant mare's serum gonadotropin( PMSG). The oocytes were matured in basal maturation solution or modified maturation solution,which was prepared by adding 200 μmol/L cysteine to the basal maturation solution. Then,the oocytes were fertilized in fertilization medium I containing 2% estrus sheep serum( ESS) or fertilization medium II containing 3 mg/ml bull serum albumin( BSA). Finally,the number of oocytes,oocyte maturation rate and cleavage rate of the lambs of different ages were determined. [Results]The average number of oocytes recovered per lamb was( 111. 00 ± 16. 97),( 139. 50 ± 28. 99),( 108. 50 ± 17. 68) and( 42. 00 ± 11. 31) for5-,7-,8-and 10-week-old Dorper × small-tailed Han lambs,respectively. The number of oocytes obtained from 5-,7-and 8-week-old lambs was significantly higher than that from 10-week-old lambs( P < 0. 05),but there was no significant difference among 5-,7-and 8-week-old lambs( P > 0. 05). The maturation rate of oocytes cultured in modified maturation solution was 3. 64% higher than that in basal maturation solution. The cleavage rate of oocytes in fertilization medium I was very significantly higher than that in fertilization medium II( P < 0. 01). [Conclusions] The results of JIVET can be improved by harvesting oocytes from lambs aged 5-8 weeks,adding a certain amount of cysteine into oocyte maturation solution,and a certain amount of ESS into fertilization medium. | Yangyi MAO Huidi LUO Guanwu ZHANG Zhiwu WANG Peng ZHAO Jun LI Hongyu GUO Shenghua ZHOU Huihui GUO Chunyan LI | 2019 | Agricultural Biotechnology2019，8，1： | 3 |
| 5 | EAST-Educational Adaptive-optics Solar Telescope显示文摘For the public having a better understanding of solar activities,the Educational Adaptive-optics Solar Telescope(EAST)was built in July 2021 and is located at the Shanghai Astronomy Museum.The EAST consists of a 65 cm aperture solar telescope with a 177-element adaptive optics system and two-channel high resolution imaging system at the Hαand TiO bands,in addition to three full disk solar telescopes at CaK,Hαand TiO bands equipped on the tube of the main telescope.In this paper,the configuration of the EAST is described.Its performance and on-sky observational results are presented.The EAST,to our knowledge,is the most advanced solar telescope for the popularization of science in the world.Due to its excellent performance,the data acquired by the EAST can also be used for research on solar physics and space weather prediction. | Changhui Rao Xuejun Rao Zhimao Du Hua Bao Cheng Li Jinlong Huang Youming Guo Libo Zhong Qing Lin Xin Ge Jinsheng Yang Xinlong Fan Yangyi Liu Dan Jia Xin Li Mei Li Ming Zhang Yuntao Cheng Jiahui Zhou Jiawen Yao Lanqiang Zhang Naiting Gu | 2022 | Research in Astronomy and Astrophysics2022，22，6： | 3 |
| 6 | Reflection on the Development of Real Estate in the Context of Block System Reform显示文摘Last year, the State Council issued the Several Opinions on Further Strengthening the Management of Urban Planning. The guideline on urban planning has sparked heated debate among Internet users over opening up gated residential communities to public road system. This paper, based on the analysis of the background and contents of block system reform, explored the problems of the implementation of the block system reform and the impact of the block system reform on the real estate in China from 3 aspects, the selling points of the high-end communities, future property management and the community elderly care model. | ZHOU Yangyi LIU Qunhong | 2017 | Journal of Landscape Research2017，9，4： | 0 |
| 7 | Systematic co-delivery of dual agonists to enhance cancer immunotherapy显示文摘In the tumor immunosuppressive microenvironment(TIME),antigen presenting cells(APCs)usually exhibit a tumor suppressor phenotype.Toll-like receptors(TLRs)agonists could reprogram M2-type macrophages to M1-type and stimulate dendritic cells(DCs)maturation.The combination of TLR7/8 and TLR9 agonists seems to have synergistic therapeutic efficacy.Here,we designed a lipid-coated mesoporous silica nanoparticle(MSNs@Lipo)for the co-delivery of TLR7/8 agonist resiquimod(R848)and TLR9 agonist CpG oligodeoxynucleotides(ODNs)(CpG@MSNs-R@L-M).R848 was firstly conjugated onto the nanoparticle via silane chemistry,which is acidic responsive drug release.Then,CpG was loaded onto the nanoparticle through the positive charge mainly from TLR7/8 agonist R848.Our in vitro experiments further indicated that both drugs have acid-responsive release properties and could be taken up by DCs and located on the endosomes of APCs.More importantly,CpG@MSNs-R@L-M could significantly improve the antitumor efficacy in B16F10 melanoma model.The mechanistic study demonstrated that CpG@MSNsR@L-M could remarkably modulate the TIME by promoting the maturation of DCs and repolarizing macrophages from M2 to M1 phenotype and facilitating the infiltration of tumor cytotoxic T cells.It was concluded that in comparison to single agonist,the codelivery of dual agonists,CpG and R848,can improve anti-tumor immune responses for cancer immunotherapy. | Xiangxia Li Guiyuan Chen Yangyi Wang Lanhong Su Bo Chen Kecheng Wu Yun Xing Zechenxi Song Ruike Dai Tianxin Liu Jiaao Zhao Zhe Xie Peijie Zhou Xiaoping Xia Yuanzeng Min | 2022 | Nano Research2022，15，9： | 0 |
| 8 | Experimental study on failure evolution mechanism of clastic rock considering cementation and intermediate principal stress显示文摘The study of clastic rock failure evolution under true triaxial stress is an important research topic;however,it is rarely studied systematically due to the limitation of monitoring technology.In this study,true triaxial compression tests were conducted on clastic rock specimens to investigate the effect of cementation and intermediate principal stress(s2)on the failure mechanism.The complete stressestrain curves were obtained,while the acoustic emission(AE)was monitored to indirectly evaluate the evo-lution of tensile and shear cracks,and crack evolution under true triaxial compression was imaged in real time by a high-speed camera.The results showed that the deformation and failure characteristics of clastic rock were closely related to the cementation type and intermediate principal stress.On the basis of the distribution characteristics of the ratio of rise time to amplitude(RA)and the average frequency(AF)of AE signals,tensile cracks of the contact cementation specimen propagated preferentially.Meanwhile,the enhancement of specimen cementation promoted the evolution of shear cracks,and the increase inσ_(2)promoted the evolution of tensile cracks.Moreover,the mesoscale cracking mechanism of clastic rock caused by cementation andσ_(2)under true triaxial compression was analyzed.The failure patterns of clastic rock under true triaxial compression were divided into three modes:structure-induced,structure-stress-induced and stress-induced failures.This study confirms the feasibility of high-speed camera technology in true triaxial testing,and has important implications for elucidating the disaster mechanism of deep tunnels in weak rocks. | Feiyan Wang Xia-Ting Feng Yangyi Zhou Xiaojun Yu | 2023 | Journal of Rock Mechanics and Geotechnical Engineering2023，15，7： | 0 |
| 9 | A rigid true triaxial apparatus for analyses of deformation and failure features of deep weak rock under excavation stress paths显示文摘The squeezing scenario in deep weak rock tunnels can hinder underground construction.However,due to the limitations of test technologies at hand,the real excavation stress path cannot be mimicked in the laboratory.Thus,the large deformation mechanism of deep weak rocks still remains unclear.For this,a true triaxial apparatus(TTA)to investigate the mechanical responses of deep weak rock under excavation stress paths in field and reveal the squeezing mechanism of deep tunnels is assembled and developed at Northeastern University,China.The apparatus can perform instantaneous unloading in s3 direction based on electromagnetism technology.In addition,uniform loading and deformation measurements can be carried out based on the proposed linked interlocking clamp and antifriction device,even if the sample has a strong dilatation deformation performance.Next,a bore trepanning is designed to capture noiseless acoustic emission(AE)signals for deep weak rock at a low threshold.Finally,two tests were are conducted using this instrument to preliminarily understand the failure and deformation features of deep weak rock based on fractured marble.The results show that the complete stressestrain curves of fractured marble have the characteristics of low strengths and large deformations,and the larger deformation and the more serious failure occur when the fractured marble enters the post-peak state after excavation.The results show that the developed apparatus is likely to be applicable for deep weak rock engineering. | Xia-Ting Feng Xiaojun Yu Yangyi Zhou Chengxiang Yang Feiyan Wang | 2023 | Journal of Rock Mechanics and Geotechnical Engineering2023，15，5： | 0 |
您所在的机构暂未开通此部分的功能，请联系管理员