Dynamic strength parameters are extensively used in mining engineering and rock mechanics.However,there are no widely accepted dynamic failure models for rocks.In this study,the dynamic punching shear strength,uniaxia...Dynamic strength parameters are extensively used in mining engineering and rock mechanics.However,there are no widely accepted dynamic failure models for rocks.In this study,the dynamic punching shear strength,uniaxial compressive strength(UCS) and tensile strength of fine-grained Fangshan marble(FM)are first measured by using a split Hopkinson pressure bar(SHPB) system.The pulse-shaping technique is then implemented to maintain the dynamic force balance in SHPB tests.Experimental results show that the dynamic punching shear strength,UCS and tensile strength increase with the loading rate.A recently developed dynamic Mohr-Coulomb theory is then used to interpret the testing data.In this model,the angle of internal friction φ is assumed to be independent of loading rate and is obtained using the static strength values.According to the dynamic Mohr-Coulomb theory,the dynamic UCS and the dynamic tensile strength are predicted from the dynamic punching shear strength.Furthermore,based on this dynamic theory,the dynamic UCS is predicted from the dynamic tensile strength.The consistency between the predicted and measured dynamic strengths demonstrates that the dynamic Mohr-Coulomb theory is applicable to FM.展开更多
The rural settlement landscape in Fangshan District has multiple values,but there is a lack ofsystematic research.Geographical environment and historical evolution in Fangshan District are analyzed,and it is thought t...The rural settlement landscape in Fangshan District has multiple values,but there is a lack ofsystematic research.Geographical environment and historical evolution in Fangshan District are analyzed,and it is thought that the combination of the two forms characteristic cultural landscape in the village.According to literature and research,villages in Fangshan District are classifi ed and summarized accordingto the time of forming,the motivation of development and the form,and they are analyzed from multidimension.Meanwhile,the problems of development and protection are concerned.Based on the aboveresearch,this paper makes a more appropriate analysis on the cultural landscape value of villages inFangshan District.Finally,the protection strategy of the whole region and key areas is proposed.展开更多
The data of REE for the dioritic enclaves of the second intrusive bodies and for apatite,sphene,magnetite,zircon amphibole,biotite,plagioclase,and K-feldspar of the host rock are systematically reported andthe feature...The data of REE for the dioritic enclaves of the second intrusive bodies and for apatite,sphene,magnetite,zircon amphibole,biotite,plagioclase,and K-feldspar of the host rock are systematically reported andthe features of their compositions,overall characteristics and changing regularities,and their petrogenetic signifi-cance are discussed.The characteristics of the compositiom of the mineral rare-earth elements and their changingregularities for the Fangshan Rock Body show that there is a cognate evolution relation between the enclavesand the rock body.It is oonsidered that the dioritic enclaves might be the product derived from the earlycrystallization of homogeneous magma.展开更多
In July 2021,ten teachers and students from the Design Innovation Practice Group of the College of Design and Art carried outaone-weekfield investigation in Fangshan county,Lyuliang city,Shanxi province during the des...In July 2021,ten teachers and students from the Design Innovation Practice Group of the College of Design and Art carried outaone-weekfield investigation in Fangshan county,Lyuliang city,Shanxi province during the designand serviceprojectof Beijing Institute of Technology's counterpart support forthe integration development of culture and tourism in Fangshan county.Fortunately,as one of the leading teachers of the practice group,l experienced the cultural journey of“Rural Revitalization,Fangshan has Me”withthe students.展开更多
Understanding the effects of microwave irradiation and thermal treatment on the dynamic compression and fragmentation properties of rocks is essential to quantify energy consumption in rock engineering.In this study,F...Understanding the effects of microwave irradiation and thermal treatment on the dynamic compression and fragmentation properties of rocks is essential to quantify energy consumption in rock engineering.In this study,Fangshan granite(FG)specimens were exposed to microwave irradiation and heat treatment.The damage of FG specimens induced by these two methods was compared using X-ray CT scanning and ultrasonic wave method.The temperatures of FG after microwave irradiation and thermal treatment were effectively evaluated using a newly proposed technique.A novelty method for precisely determining the geometric features of fragments is developed to estimate the fragmentation energy.Thus,the dynamic uniaxial compressive strength(UCS),the dynamic fragmentation characteristics,and the fragmentation energy of FG after these two pretreatment methods can be reasonably compared.The noticeable distinction of loading rate effect on the dynamic UCS of FG between these two pretreatment methods is first observed.A relationship is established between the dynamic UCS and the damage induced by microwave irradiation and heat treatment.Moreover,fragmentation energy fan analysis is introduced to accurately compare the fragmentation properties of FG after two pretreatment methods in dynamic compression tests.展开更多
北京房山侵入岩体主要由石英二长闪长岩单元和三种不同结构的花岗闪长岩单元组成,岩体中广泛分布的镁铁质微粒包体、富集暗色矿物的线状条带以及各岩相单元的非渐变接触关系等宏观特征,指示岩体的形成与岩浆混合作用有密切联系。122个...北京房山侵入岩体主要由石英二长闪长岩单元和三种不同结构的花岗闪长岩单元组成,岩体中广泛分布的镁铁质微粒包体、富集暗色矿物的线状条带以及各岩相单元的非渐变接触关系等宏观特征,指示岩体的形成与岩浆混合作用有密切联系。122个斜长石成分剖面电子探针分析表明,它们众数成分为 An=29的更长石。但是,其成分变化范围极宽(An=14～56),晶体内不同部位的成分有很大差别,出现正常环带的 An 值较低(14～42),内环带的 An 值较高(24～56)的特殊情况,指示斜长石结晶环境的改变,暗示具有富钙基性岩浆的加入。从岩体边部到中心,斜长石 An 牌号逐渐降低,但相邻岩相单元之间有较大的重叠,表明不同岩石单元中的斜长石成分主要受控于岩浆成分的变化,与分离结晶作用无关。斜长石的韵律性环带、特别是内环带的发育则是岩浆混合作用机制的有力证据。基性岩浆的反复注入不仅改变寄主岩浆的成分,而且也控制了它的温度、定位机制和岩石的结构特征。因此,房山岩体的形成过程还包含了镁铁质岩浆多次注入的历史,并且从外到里基性岩浆的作用逐渐减弱。展开更多
基金provided by the Natural Sciences and Engineering Research Council of Canada(NSERC)through the Discovery Grant No.72031326
文摘Dynamic strength parameters are extensively used in mining engineering and rock mechanics.However,there are no widely accepted dynamic failure models for rocks.In this study,the dynamic punching shear strength,uniaxial compressive strength(UCS) and tensile strength of fine-grained Fangshan marble(FM)are first measured by using a split Hopkinson pressure bar(SHPB) system.The pulse-shaping technique is then implemented to maintain the dynamic force balance in SHPB tests.Experimental results show that the dynamic punching shear strength,UCS and tensile strength increase with the loading rate.A recently developed dynamic Mohr-Coulomb theory is then used to interpret the testing data.In this model,the angle of internal friction φ is assumed to be independent of loading rate and is obtained using the static strength values.According to the dynamic Mohr-Coulomb theory,the dynamic UCS and the dynamic tensile strength are predicted from the dynamic punching shear strength.Furthermore,based on this dynamic theory,the dynamic UCS is predicted from the dynamic tensile strength.The consistency between the predicted and measured dynamic strengths demonstrates that the dynamic Mohr-Coulomb theory is applicable to FM.
文摘The rural settlement landscape in Fangshan District has multiple values,but there is a lack ofsystematic research.Geographical environment and historical evolution in Fangshan District are analyzed,and it is thought that the combination of the two forms characteristic cultural landscape in the village.According to literature and research,villages in Fangshan District are classifi ed and summarized accordingto the time of forming,the motivation of development and the form,and they are analyzed from multidimension.Meanwhile,the problems of development and protection are concerned.Based on the aboveresearch,this paper makes a more appropriate analysis on the cultural landscape value of villages inFangshan District.Finally,the protection strategy of the whole region and key areas is proposed.
基金the Scientific Development Fund of Peking UniversityZhongguancun Testing Fund Beijing,Chjna
文摘The data of REE for the dioritic enclaves of the second intrusive bodies and for apatite,sphene,magnetite,zircon amphibole,biotite,plagioclase,and K-feldspar of the host rock are systematically reported andthe features of their compositions,overall characteristics and changing regularities,and their petrogenetic signifi-cance are discussed.The characteristics of the compositiom of the mineral rare-earth elements and their changingregularities for the Fangshan Rock Body show that there is a cognate evolution relation between the enclavesand the rock body.It is oonsidered that the dioritic enclaves might be the product derived from the earlycrystallization of homogeneous magma.
文摘In July 2021,ten teachers and students from the Design Innovation Practice Group of the College of Design and Art carried outaone-weekfield investigation in Fangshan county,Lyuliang city,Shanxi province during the designand serviceprojectof Beijing Institute of Technology's counterpart support forthe integration development of culture and tourism in Fangshan county.Fortunately,as one of the leading teachers of the practice group,l experienced the cultural journey of“Rural Revitalization,Fangshan has Me”withthe students.
基金supported by the National Natural Science Foundation of China(Nos.51879184 and 12172253).
文摘Understanding the effects of microwave irradiation and thermal treatment on the dynamic compression and fragmentation properties of rocks is essential to quantify energy consumption in rock engineering.In this study,Fangshan granite(FG)specimens were exposed to microwave irradiation and heat treatment.The damage of FG specimens induced by these two methods was compared using X-ray CT scanning and ultrasonic wave method.The temperatures of FG after microwave irradiation and thermal treatment were effectively evaluated using a newly proposed technique.A novelty method for precisely determining the geometric features of fragments is developed to estimate the fragmentation energy.Thus,the dynamic uniaxial compressive strength(UCS),the dynamic fragmentation characteristics,and the fragmentation energy of FG after these two pretreatment methods can be reasonably compared.The noticeable distinction of loading rate effect on the dynamic UCS of FG between these two pretreatment methods is first observed.A relationship is established between the dynamic UCS and the damage induced by microwave irradiation and heat treatment.Moreover,fragmentation energy fan analysis is introduced to accurately compare the fragmentation properties of FG after two pretreatment methods in dynamic compression tests.
文摘北京房山侵入岩体主要由石英二长闪长岩单元和三种不同结构的花岗闪长岩单元组成,岩体中广泛分布的镁铁质微粒包体、富集暗色矿物的线状条带以及各岩相单元的非渐变接触关系等宏观特征,指示岩体的形成与岩浆混合作用有密切联系。122个斜长石成分剖面电子探针分析表明,它们众数成分为 An=29的更长石。但是,其成分变化范围极宽(An=14～56),晶体内不同部位的成分有很大差别,出现正常环带的 An 值较低(14～42),内环带的 An 值较高(24～56)的特殊情况,指示斜长石结晶环境的改变,暗示具有富钙基性岩浆的加入。从岩体边部到中心,斜长石 An 牌号逐渐降低,但相邻岩相单元之间有较大的重叠,表明不同岩石单元中的斜长石成分主要受控于岩浆成分的变化,与分离结晶作用无关。斜长石的韵律性环带、特别是内环带的发育则是岩浆混合作用机制的有力证据。基性岩浆的反复注入不仅改变寄主岩浆的成分,而且也控制了它的温度、定位机制和岩石的结构特征。因此,房山岩体的形成过程还包含了镁铁质岩浆多次注入的历史,并且从外到里基性岩浆的作用逐渐减弱。
