Recent geological study and survey on the scale of 1: 50000 in northern Guangxi have made some advancements: meta-basic-ultrabasic rocks which occured as bedding injection sheets in the Sanrnenjie formation of the Pro...Recent geological study and survey on the scale of 1: 50000 in northern Guangxi have made some advancements: meta-basic-ultrabasic rocks which occured as bedding injection sheets in the Sanrnenjie formation of the Proterozoic Danzhou group and caused contact metamorphism or hydrothermal alteration in adjacent wallrocks, were originated in extensional environment. Basic rocks belong to deep-sea tholeiite. TLe meta-basic -ultrabasic rocks sufferred intense deformation partitioning, resulting in lenticular network which was composed of mylonite zones in highly de formed field and lensoids in less- or non-deformed field. This structural pattern was explained as "melange" or "non-rooted cool intrusion " by previous workers. The deformation partitioning was mainly pure shearing in the early stage plus simple shearing in the later stage. This evolution was closely related to progressive deformation of the Guangxi orogeny.展开更多
Understanding the mechanical properties of the lithologies is crucial to accurately determine the horizontal stress magnitude.To investigate the correlation between the rock mass properties and maximum horizontal stre...Understanding the mechanical properties of the lithologies is crucial to accurately determine the horizontal stress magnitude.To investigate the correlation between the rock mass properties and maximum horizontal stress,the three-dimensional(3D)stress tensors at 89 measuring points determined using an improved overcoring technique in nine mines in China were adopted,a newly defined characteristic parameter C_(ERP)was proposed as an indicator for evaluating the structural properties of rock masses,and a fuzzy relation matrix was established using the information distribution method.The results indicate that both the vertical stress and horizontal stress exhibit a good linear growth relationship with depth.There is no remarkable correlation between the elastic modulus,Poisson's ratio and depth,and the distribution of data points is scattered and messy.Moreover,there is no obvious relationship between the rock quality designation(RQD)and depth.The maximum horizontal stress σ_(H) is a function of rock properties,showing a certain linear relationship with the C_(ERP)at the same depth.In addition,the overall change trend of σ_(H) determined by the established fuzzy identification method is to increase with the increase of C_(ERP).The fuzzy identification method also demonstrates a relatively detailed local relationship betweenσ_H and C_(ERP),and the predicted curve rises in a fluctuating way,which is in accord well with the measured stress data.展开更多
目的:观察化瘀通络灸对血管性痴呆大鼠Ras同源物基因组成员A(Ras homolog gene family member A,RhoA)/Rho激酶(Rho associated protein kinase, ROCK)轴突生长抑制性信号通路相关蛋白的影响,探讨其治疗血管性痴呆的机制。方法:使用Mor...目的:观察化瘀通络灸对血管性痴呆大鼠Ras同源物基因组成员A(Ras homolog gene family member A,RhoA)/Rho激酶(Rho associated protein kinase, ROCK)轴突生长抑制性信号通路相关蛋白的影响,探讨其治疗血管性痴呆的机制。方法:使用Morris水迷宫筛除贴壁、原地旋转或溺水的Wistar大鼠,将符合条件大鼠分为假手术组、造模组。假手术组暴露大鼠颈总动脉;造模组用改良的双侧颈总动脉永久结扎术制备血管性痴呆大鼠模型,术后3 d用水迷宫对大鼠进行模型鉴定,将合格者随机分为模型组、艾灸组和西药组。于鉴定次日对大鼠进行治疗,艾灸组悬灸百会、大椎、神庭,20 min/次,1次/d, 1周为1疗程,2个疗程间休息1 d,共3个疗程;西药组用吡拉西坦溶液灌胃,2次/d;假手术组、模型组行灸架固定。治疗结束,取大鼠脑组织,用免疫荧光单染法、蛋白免疫印迹法检测其脑内目的蛋白RhoA、Rho相关螺旋卷曲蛋白激酶Ⅱ(Rho protein-related curl spiral kinase-Ⅱ,ROCKⅡ)、肌球蛋白轻链磷酸化(Phosphorylation of myosin light chain, P-MLC)的阳性表达。结果:模型组大鼠海马、皮质RhoA、ROCKⅡ、P-MLC蛋白表达高于假手术组(P<0.01);艾灸组、西药组海马和皮质RhoA、ROCKⅡ、P-MLC蛋白表达较模型组低(P<0.05);艾灸组皮质ROCKⅡ蛋白表达较西药组稍低(P<0.05);艾灸组与西药组海马ROCKⅡ、海马与皮质RhoA、P-MLC蛋白表达差异无统计学意义(P>0.05)。结论:化瘀通络灸可能是通过下调RhoA/ROCK轴突生长抑制性信号通路相关蛋白的表达提高血管性痴呆大鼠的记忆力,从而发挥治疗血管性痴呆的作用。展开更多
The nature of rock fragmentation affects the downstream mining processes like loading, hauling, and crushing the blasted rock. Therefore, it is important to evaluate rock fragmentation after blasting for choosing or d...The nature of rock fragmentation affects the downstream mining processes like loading, hauling, and crushing the blasted rock. Therefore, it is important to evaluate rock fragmentation after blasting for choosing or designing optimal strategies for these processes. However, current techniques of rock fragmentation analysis such as sieving, image-based analysis, empirical methods or artificial intelligence-based methods entail different practical challenges, for example, excessive processing time, higher costs, applicability issues in underground environments, user-biasness, accuracy issues, etc. A classification model has been developed by utilizing image analysis techniques to overcome these challenges. The model was tested on about 7500 videos of load-haul-dump (LHD) buckets with blasted material from Malmberget iron ore mine in Sweden. A Kernel-based support vector machine (SVM) method was utilized to extract frames comprising loaded LHD buckets. Then, the blasted rock in the buckets was classified into five distinct categories using the bagging k-nearest neighbor (KNN) technique. The results showed 99.8% and 89.8% accuracy for kernel-based SVM and bagging KNN classifiers, respectively. The developed framework is efficient in terms of the operation time, cost and practicability for different mines and variate amounts of rock masses.展开更多
The preservation condition of historical buildings is closely related to their ventilation environment.This study focuses on the rock temples in Wudang Mountain,specifically comparing the ventilation conditions of Yin...The preservation condition of historical buildings is closely related to their ventilation environment.This study focuses on the rock temples in Wudang Mountain,specifically comparing the ventilation conditions of Yinxian Rock and Huayang Rock.The following conclusions are drawn:(1)The main wind direction at Yinxian Rock aligns with its orientation,which is an easterly wind,while Huayang Rock experiences a westerly wind,deviating from its southwestern entrance;(2)Huayang Rock has significantly lower wind speeds compared to Yinxian Rock,with minimal airflow;(3)The surrounding environment of Huayang Rock features steep terrain,dense tree cover,and the presence of railings and other structures that impede wind entry into the cave,whereas Yinxian Rock is surrounded by fewer trees and has a flat terrain;(4)In terms of cave morphology,Yinxian Rock is completely open on the east side,while Huayang Rock's opening accounts for only half of its area and is not directly aligned with the rock temple.In summary,Huayang Rock's ventilation environment is inferior to that of Yinxian Rock,leading to more severe pathologies.It is inferred that Huayang Rock's preservation issues are closely related to its poor ventilation environment.Therefore,improving its ventilation conditions is crucial for preventive conservation.Using environmental simulation,this study compares the ventilation conditions of Huayang Rock under different wind directions and speeds,identifies the two most ideal scenarios,and proposes several feasible solutions.展开更多
The squeezing deformation of surrounding rock is an important factor restricting the safe construction and long-term operation of tunnels when a tunnel passes through soft strata with high ground stress.Under such sof...The squeezing deformation of surrounding rock is an important factor restricting the safe construction and long-term operation of tunnels when a tunnel passes through soft strata with high ground stress.Under such soft rock geological conditions,the large deformation of the surrounding rock can easily lead to the failure of supporting structures,including shotcrete cracks,spalling,and steel arch distortion.To improve the lining support performance during the large deformation of squeezed surrounding rock,this work selects aluminum foam with densities of 0.25 g/cm3,0.42 g/cm3 and 0.61 g/cm3 as the buffer layer material and carries out uniaxial confined compression tests.Through the evaluation and analysis of energy absorption and the comparison of the yield pressure of aluminum foam with those of other cushioning materials and yield pressure support systems,the strength,deformation and energy absorption of aluminum foam with a density of 0.25 g/cm3 meet the yield pressure performance requirements.The numerical model of the buffer layer yielding support system is then established via the finite element analysis software ABAQUS,and the influence of the buffer layer setting on the lining support is analyzed.Compared with the conventional support scheme,the addition of an aluminum foam buffer layer can reduce the stress and deformation of the primary support and secondary lining.The maximum and minimum principal stresses of the primary support are reduced by 13%and 15%,respectively.The maximum and minimum principal stresses of the secondary lining are reduced by 15%and 12%,respectively,and the displacement deformation of the secondary lining position is reduced by 15%.In summary,the application of aluminum foam buffer layer can reduce the stress and deformation of the primary support and secondary lining,improve the stress safety of the support and reduce the deformation of the support.展开更多
In hilly regions,the existence of surface cracks in rock mass induces a potential threat to structural stability.Thus,the present research aims to explore the impact of surface cracks on the loadbearing capacity of st...In hilly regions,the existence of surface cracks in rock mass induces a potential threat to structural stability.Thus,the present research aims to explore the impact of surface cracks on the loadbearing capacity of strip footing placed on the rock mass.By taking into account the various boundary constraints across the surface of crack edges,the study investigates the presence of two categories of surface cracks,namely(1)separated crack,and(2)fine crack.The lower bound limit analysis is employed in conjunction with the finite element method(LBFELA)to conduct the numerical analysis.In order to evaluate rock mass yielding,the power conic programming(PCP)method is utilized to implement the generalized Hoek-Brown(GHB)failure criterion.The stability of the strip footing is analyzed by determining the bearing capacity factor(Nσγ),which is presented in the form of design charts by varying the strength parameters of rock,including the Geological Strength Index(GSI),Hoek-Brown material parameter(mi),Disturbance factor(D),and Normalised Uniaxial Compressive Strength(σci/γB),whereγis the unit weight of rock mass,and B is the width of strip footing.The study also investigates the impact of cracks on strip footings,considering different positions of the crack(LC)and depths of the crack(DC).The results demonstrate that the influence of the fine crack is only noticeable until the LC/B ratio reaches 6.However,for the separated crack,its impact remains significant even when the LC/B ratio exceeds 16.The appearance of fine crack at the edge of the footing results in a decrease in the magnitude Nσγof up to 45%,indicating a substantial reduction in the stability of the footing.The failure patterns are presented and discussed in detail for various cases in this study to examine the effect of surface cracks on the strip footing and to address the extent of the plastic collapse.展开更多
文摘Recent geological study and survey on the scale of 1: 50000 in northern Guangxi have made some advancements: meta-basic-ultrabasic rocks which occured as bedding injection sheets in the Sanrnenjie formation of the Proterozoic Danzhou group and caused contact metamorphism or hydrothermal alteration in adjacent wallrocks, were originated in extensional environment. Basic rocks belong to deep-sea tholeiite. TLe meta-basic -ultrabasic rocks sufferred intense deformation partitioning, resulting in lenticular network which was composed of mylonite zones in highly de formed field and lensoids in less- or non-deformed field. This structural pattern was explained as "melange" or "non-rooted cool intrusion " by previous workers. The deformation partitioning was mainly pure shearing in the early stage plus simple shearing in the later stage. This evolution was closely related to progressive deformation of the Guangxi orogeny.
基金financially supported by the National Natural Science Foundation of China(No.52204084)the Open Research Fund of the State Key Laboratory of Coal Resources and safe Mining,CUMT,China(No.SKLCRSM 23KF004)+3 种基金the Interdisciplinary Research Project for Young Teachers of USTB(Fundamental Research Funds for the Central Universities),China(No.FRF-IDRY-GD22-002)the Fundamental Research Funds for the Central Universities and the Youth Teacher International Exchange and Growth Program,China(No.QNXM20220009)the National Key R&D Program of China(Nos.2022YFC2905600 and 2022 YFC3004601)the Science,Technology&Innovation Project of Xiongan New Area,China(No.2023XAGG0061)。
文摘Understanding the mechanical properties of the lithologies is crucial to accurately determine the horizontal stress magnitude.To investigate the correlation between the rock mass properties and maximum horizontal stress,the three-dimensional(3D)stress tensors at 89 measuring points determined using an improved overcoring technique in nine mines in China were adopted,a newly defined characteristic parameter C_(ERP)was proposed as an indicator for evaluating the structural properties of rock masses,and a fuzzy relation matrix was established using the information distribution method.The results indicate that both the vertical stress and horizontal stress exhibit a good linear growth relationship with depth.There is no remarkable correlation between the elastic modulus,Poisson's ratio and depth,and the distribution of data points is scattered and messy.Moreover,there is no obvious relationship between the rock quality designation(RQD)and depth.The maximum horizontal stress σ_(H) is a function of rock properties,showing a certain linear relationship with the C_(ERP)at the same depth.In addition,the overall change trend of σ_(H) determined by the established fuzzy identification method is to increase with the increase of C_(ERP).The fuzzy identification method also demonstrates a relatively detailed local relationship betweenσ_H and C_(ERP),and the predicted curve rises in a fluctuating way,which is in accord well with the measured stress data.
文摘The nature of rock fragmentation affects the downstream mining processes like loading, hauling, and crushing the blasted rock. Therefore, it is important to evaluate rock fragmentation after blasting for choosing or designing optimal strategies for these processes. However, current techniques of rock fragmentation analysis such as sieving, image-based analysis, empirical methods or artificial intelligence-based methods entail different practical challenges, for example, excessive processing time, higher costs, applicability issues in underground environments, user-biasness, accuracy issues, etc. A classification model has been developed by utilizing image analysis techniques to overcome these challenges. The model was tested on about 7500 videos of load-haul-dump (LHD) buckets with blasted material from Malmberget iron ore mine in Sweden. A Kernel-based support vector machine (SVM) method was utilized to extract frames comprising loaded LHD buckets. Then, the blasted rock in the buckets was classified into five distinct categories using the bagging k-nearest neighbor (KNN) technique. The results showed 99.8% and 89.8% accuracy for kernel-based SVM and bagging KNN classifiers, respectively. The developed framework is efficient in terms of the operation time, cost and practicability for different mines and variate amounts of rock masses.
基金Supported by the National Natural Science Foundation of China(Grant No.52278042)for the research on"Architectural issue mechanisms and defense of architectural heritage under harsh environments-Taking the rock temples of Wudang Mountain as an example."。
文摘The preservation condition of historical buildings is closely related to their ventilation environment.This study focuses on the rock temples in Wudang Mountain,specifically comparing the ventilation conditions of Yinxian Rock and Huayang Rock.The following conclusions are drawn:(1)The main wind direction at Yinxian Rock aligns with its orientation,which is an easterly wind,while Huayang Rock experiences a westerly wind,deviating from its southwestern entrance;(2)Huayang Rock has significantly lower wind speeds compared to Yinxian Rock,with minimal airflow;(3)The surrounding environment of Huayang Rock features steep terrain,dense tree cover,and the presence of railings and other structures that impede wind entry into the cave,whereas Yinxian Rock is surrounded by fewer trees and has a flat terrain;(4)In terms of cave morphology,Yinxian Rock is completely open on the east side,while Huayang Rock's opening accounts for only half of its area and is not directly aligned with the rock temple.In summary,Huayang Rock's ventilation environment is inferior to that of Yinxian Rock,leading to more severe pathologies.It is inferred that Huayang Rock's preservation issues are closely related to its poor ventilation environment.Therefore,improving its ventilation conditions is crucial for preventive conservation.Using environmental simulation,this study compares the ventilation conditions of Huayang Rock under different wind directions and speeds,identifies the two most ideal scenarios,and proposes several feasible solutions.
基金the support of the National Natural Science Foundation of China(Grant No.42207199)Scientific Research Project of Education of Zhejiang Province(No.Y202351343)+1 种基金Zhejiang Postdoctoral Scientific Research Project(Grant Nos.ZJ2022155,ZJ2022156)Zhejiang Province International Science and Technology Cooperation Base Open Fund Project(IBGDP-2023-01)。
文摘The squeezing deformation of surrounding rock is an important factor restricting the safe construction and long-term operation of tunnels when a tunnel passes through soft strata with high ground stress.Under such soft rock geological conditions,the large deformation of the surrounding rock can easily lead to the failure of supporting structures,including shotcrete cracks,spalling,and steel arch distortion.To improve the lining support performance during the large deformation of squeezed surrounding rock,this work selects aluminum foam with densities of 0.25 g/cm3,0.42 g/cm3 and 0.61 g/cm3 as the buffer layer material and carries out uniaxial confined compression tests.Through the evaluation and analysis of energy absorption and the comparison of the yield pressure of aluminum foam with those of other cushioning materials and yield pressure support systems,the strength,deformation and energy absorption of aluminum foam with a density of 0.25 g/cm3 meet the yield pressure performance requirements.The numerical model of the buffer layer yielding support system is then established via the finite element analysis software ABAQUS,and the influence of the buffer layer setting on the lining support is analyzed.Compared with the conventional support scheme,the addition of an aluminum foam buffer layer can reduce the stress and deformation of the primary support and secondary lining.The maximum and minimum principal stresses of the primary support are reduced by 13%and 15%,respectively.The maximum and minimum principal stresses of the secondary lining are reduced by 15%and 12%,respectively,and the displacement deformation of the secondary lining position is reduced by 15%.In summary,the application of aluminum foam buffer layer can reduce the stress and deformation of the primary support and secondary lining,improve the stress safety of the support and reduce the deformation of the support.
基金supported by the Centre for Development of Advanced Computing (CDAC), Pune
文摘In hilly regions,the existence of surface cracks in rock mass induces a potential threat to structural stability.Thus,the present research aims to explore the impact of surface cracks on the loadbearing capacity of strip footing placed on the rock mass.By taking into account the various boundary constraints across the surface of crack edges,the study investigates the presence of two categories of surface cracks,namely(1)separated crack,and(2)fine crack.The lower bound limit analysis is employed in conjunction with the finite element method(LBFELA)to conduct the numerical analysis.In order to evaluate rock mass yielding,the power conic programming(PCP)method is utilized to implement the generalized Hoek-Brown(GHB)failure criterion.The stability of the strip footing is analyzed by determining the bearing capacity factor(Nσγ),which is presented in the form of design charts by varying the strength parameters of rock,including the Geological Strength Index(GSI),Hoek-Brown material parameter(mi),Disturbance factor(D),and Normalised Uniaxial Compressive Strength(σci/γB),whereγis the unit weight of rock mass,and B is the width of strip footing.The study also investigates the impact of cracks on strip footings,considering different positions of the crack(LC)and depths of the crack(DC).The results demonstrate that the influence of the fine crack is only noticeable until the LC/B ratio reaches 6.However,for the separated crack,its impact remains significant even when the LC/B ratio exceeds 16.The appearance of fine crack at the edge of the footing results in a decrease in the magnitude Nσγof up to 45%,indicating a substantial reduction in the stability of the footing.The failure patterns are presented and discussed in detail for various cases in this study to examine the effect of surface cracks on the strip footing and to address the extent of the plastic collapse.
文摘目的 探讨七味白术散对糖尿病模型大鼠海马组织RhoA/ROCK2通路的作用,并探讨其改善糖尿病脑病的作用机制。方法 以高脂饲料结合STZ复制并筛选出符合条件的DE大鼠模型,随机分为模型组、七味白术散低、中、高剂量组、西药组。另设不造模的正常组。采用Morris水迷宫实验观察各组大鼠学习和空间记忆能力,用ELISA法检测海马组织中β-淀粉样蛋白42(β-amyloid protein 42,Aβ42)与磷酸化Tau蛋白(p-tau)含量,用RT-PCR法和Western blot检测海马样本中突触相关蛋白Syn、突触后致密物质PSD95(Postsynaptic density protein-95,PSD95)、RhoA、ROCK2的表达水平。结果 在检测各海马样本中Syn、PSD95、RhoA及ROCK2相对表达后,发现七味白术散干预4周后,模型组与正常组比较:RhoA、ROCK2表达水平显著升高,Syn、PSD95表达水平显著下降,差异有统计学意义(P<0.01),提示DE大鼠海马组织中的RhoA/ROCK2信号通路被抑制。中剂量组与模型组比较后发现:RhoA、ROCK2表达水平显著下降,Syn、PSD95表达水平显著上升,差异有统计学意义(P<0.01),表明七味白术散可能通过抑制RhoA/ROCK2通路,并调节突触可塑性。结论 七味白术散可能是通过抑制RhoA/ROCK2信号通路并上调突触可塑性来改善患有DE的大鼠。
