Effect of Freeze-Thaw Cycles on Mechanical Properties and Permeability of Red Sandstone under Triaxial Compression   总被引：1，自引：1，他引：0  

YU Jin  CHEN Xu  LI Hong  ZHOU Jia-wen  CAI Yan-yan 《山地科学学报》2015,(1):218-231

Geological disasters will happen in cold regions because of the effects of freeze-thaw cycles on rocks or soils, so studying the effects of these cycles on the mechanical characteristics and permeability properties of rocks is very important. In this study,red sandstone samples were frozen and thawed with 0,4, 8 and 12 cycles, each cycle including 12 h of freezing and 12 h of thawing. The P-wave velocities of these samples were measured, and the mechanical properties and evolution of the steady-state permeabilities were investigated in a series of uniaxial and triaxial compression tests. Experimental results show that, with the increasing of cyclic freeze-thaw times, the P-wave velocity of the red sandstone decreases. The number of freeze-thaw cycles has a significant influence on the uniaxial compressive strength, elastic modulus, cohesion, and angle of internal friction. The evolution of permeability of the rock samples after cycles of freeze-thaw in a complete stress-strain process under triaxial compression is closely related to the variation of the microstructure in the rock. There is a highly corresponding relationship between volumetric strain and permeability with axial strain in all stages of the stress-strain behaviour.  相似文献   

REE and Sr-Nd Isotope Geochemistry for Yixian Fluorite Deposit,Western Liaoning Province,China,and Its Geological Implications     

孙祥  邓军  杨立强  王庆飞  杨子荣  龚庆杰  王长明 《中国地质大学学报(英文版)》2010,(2)

Up to now,there were no systematic studies of geochemistry and isotopic age for the Yixian(义县) fluorite deposit,western Liaoning(辽宁) Province,China.Based on the analysis of metallogenic geological setting,we studied the REE,Rb-Sr and Sm-Nd isotopes.The chondrite-normalized REE patterns of fluorite are characterized by moderate LREE depletion(LREE/HREE=0.95-3.57,(La/Yb)N=0.08-2.84) and enrichment of Sr(146×10-6-596×10-6) and moderately positive Eu anomalies(δEu=1.10-1.34),which are similar to those of the ho...  相似文献   

三叠纪嘉陵江期华蓥山同沉积断层的沉积、储层响应   总被引：1，自引：0，他引：1  

刘宏  孙振  李卓沛  李凌  聂勇  吴家杰  周小刚  谭秀成 《地层学杂志》2010,(3)

对于断裂带在地质历史时期活动特点的认识,因多期次、不同活动性质的叠加改造而难以确定。以四川盆地南部嘉陵江组为例,通过三叠纪嘉陵江期华蓥山断裂带两侧的沉积、储层的研究发现沉积、储层响应与断面倾向南东、东侧下降的观点矛盾。主要表现为:在非浅滩化的嘉三期,紧邻断裂带西北侧的下降盘地层异常增厚;浅滩化的嘉一晚期—嘉二1期,东南侧的泸州古隆起地区颗粒岩累计厚度较西北侧增厚;另外,断层东南侧的颗粒岩发育早期岩溶型储层,而在西北侧这类储层欠发育。结果表明在三叠纪嘉陵江期华蓥山断裂带的断面倾向北西,为西侧下降的同沉积正断层。  相似文献   

Connections Between Different Types of El Nio and Southern/Northern Oscillation          下载免费PDF全文

彭京备  张庆云  陈烈庭 《Acta Meteorologica Sinica》2011,(4)

It has long been acknowledged that there are two types of El Nio events, i.e., the eastern Pacific El Nio (EE) and the central Pacific El Nio (CE), according to the initial position of the anomalous warm water and its propagation direction. In this paper, the oceanic and atmospheric evolutions and the possible mechanisms of the two types of El Nio events were examined. It is found that all the El Nio events, CE or EE, could be attributed to the joint impacts of the eastward advection of warm water from...  相似文献   

Climatic characteristics of convective and stratiform precipitation over the Tropical and Subtropical areas as derived from TRMM PR   总被引：4，自引：0，他引：4  

LIU Peng  LI ChongYin  WANG Yu  FU YunFei 《中国科学:地球科学(英文版)》2013,(3):375-385

Climatic characteristics of convective and stratiform precipitation over the Tropical and Subtropical areas are investigated based on the measurements of Tropical Rainfall Measuring Mission’s(TRMM) Precipitation Radar(PR) from 1998 to 2007.Results indicate that convective precipitation are distributed mainly over the Intertropical Convergence Zone(ITCZ),the South Pacific Convergence Zone(SPCZ),the Asian Monsoon Region,regions between the South America and the Mid-America,and the Tropical Africa where the frequencies lie between 1% and 2%.But in four seasons,total area fractions of convective precipitation frequencies less than 1% all exceed 85%.The frequencies of stratiform precipitation are much higher than those of convective precipitation,and total area fractions of stratiform precipitation frequencies >1% are over 55% during four seasons.However,frequencies of the two rain types show not only remarkable regionality,but also distinct seasonal variations.Conditional rain rates of convective precipitation range from 6 to 14 mm/h whereas those of stratiform precipitation are smaller than 4 mm/h.Meanwhile,rain tops of convective precipitation are higher than those of stratiform precipitation.The mean profiles of the two rain types show significant latitudinal dependency.And the seasonal variations of precipitation profiles are displayed mainly in the variations of rain tops.The frequencies and conditional rain rates of both rain types over ocean are higher than those over land,but rain tops are just the opposite.Moreover,the seasonal variations of both rain types over ocean are weaker than those over land because of the different stable states of underlying surfaces.  相似文献   

地震动力分析的经典方法与现代计算技术     

万召侗  姚运生 《大地测量与地球动力学》2004,24(1):111-116

回顾了体系地震动力分析的历史过程，并对地震动力分析的传统理论方法、近似方法和现代计算技术从新的角度加以阐述，同时给出体系地震动力分析的应用前景，以促进经典的传统理论方法、近似方法和现代计算技术的综合和在实际工程中的应用，形成系统而完整的地震动力分析体系。  相似文献   

Research on method of pressure grouting piling of driven tube     

Dianqi PAN Zupei ZHANG Diancai PAN Yong CHEN Maosen TAN 《东北亚地学研究》2006,9(2):194-196

The pressure grouting pile of driven tube can improve the load bearing capacity of the single pile from the mechanism of pressure grouting pile of driven tube.On the basis of analyzing the mechanism,the authors designed the machines and tools of pressure grouting,determined the operating manufacture and technology parameter on the pressure grouting secondly.The result shows that the pressure grouting pile of driven tube not only changes the pile type but also reduce the length of the pile and its engineering cost,it enhances the load bearing capacity of single pile an the same time.  相似文献   

Comparative Analysis of Seismic Response Characteristics of Pile-Soil-Stnicture Interaction System     

KONG Desen  LUAN Maotian  and WANG Weiming School of Civil Engineering  Harbin Institute of Technology  Harbin  P.R.China School of Civil  Architectural Engineering  Shandong University of Science  Technology  Qingdao  P.R.China Institute of Geotechnical Engineering  Dalian University of Technology  Dalian  P.R.China 《中国海洋大学学报(英文版)》2006,(1)

The study on the earthquake-resistant performance of a pile-soil-structure interaction system is a relatively complicated and primarily important issue in civil engineering practice. In this paper, a computational model and computation procedures for pile-supported structures, which can duly consider the pile-soil interaction effect, are established by the finite element method. Numerical implementation is made in the time domain. A simplified approximation for the seismic response analysis of pile-soil-structure systems is briefly presented. Then a comparative study is performed for an engineering example with numerical results computed respectively by the finite element method and the simplified method. Through comparative analysis, it is shown that the results obtained by the simplified method well agree with those achieved by the finite element method. The numerical results and findings will offer instructive guidelines for earthquake-resistant analysis and design of pile-supported structures.  相似文献   

Spatial analysis of the impact of land-use on surface runoff and soil erosion-a case study of western Jilin     

Juana P Moiwo 《东北亚地学研究》2006,9(1):80-93

IntroductionNever before hasit beensotrue than now,thatlandis ali mitedresource.Population growth and as-sociated human activities,especially agricultureacross the world have not only led to land degrada-tion,but soil loss at rates that have pushed arablesoils to frontier thresholds.In the absence of arablesoil,the human environment would cease to groworeven demise(Ramet al.,2006).Studies haveshownthat in many regions of the world,runoff andsoil erosion differ withland-use type.Judson(1965)re…  相似文献   

创造良好地质环境 服务地方经济建设——山东省庆云县实施地下水环境质量调查评价          下载免费PDF全文

德州市国土资源局地环科 《山东国土资源》2003,19(6):27-27

庆云县是山东省欠发达县区之一,也是国家级重点扶贫县。由于该县自然条件较差,多年来,淡水资源的匮乏一直困扰着全县工农业生产的发展和人民生活水平的提高。近几年来,随着人类经济活动的加剧,又出现了许多新的环境地质问题,严重阻碍了全县社会经济的持续发展。为此,庆云县实施了地下水环境质量调查评价。该项目主要是调查评价目前地下水环境质量状况,为合理开发和保护地下水资源,改善生态环境,促进地方经济发展,提出地质科学依据。其主要工作任务:一是调查了解区内地形、地貌及水文地质条件,初步查明浅层地下水含水层的埋藏规律、分布特征;…  相似文献