Reliability analysis of strength of cement treated soils     

《Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards》2013,7(3-4):157-162

The design strength of cement treated soils and its variability are influenced by various contributing factors such as inherent variability of the soft ground as well as variations in the quantities of the additives used for improvement. To consider these variations, geotechnical designs use the factor of safety approach. This paper shows that the reliability-based analysis enables a rational choice of a design strength value for the cement-stabilised soft soil, considering the variations in the influencing input parameters in an appropriate manner. An approach for identifying the important variables governing the strength behaviour of improved soft soils is also illustrated.  相似文献   

河东煤田三交区块水文地质条件控气的正负耦合效应     

周济  袁远  王孝亮  曹代勇 《中国煤炭地质》2013,25(5)

煤层气的开采受多种地质因素的影响,不同区块的主控因素各不相同.山西河东煤田三交区块构造简单,煤岩渗透率和临储比相对其他区块较优,含气性良好,是煤层气开采的优势区块,但是区内不同气井产气量却相差很大.结合现场排采井采出水的水质分析实验与stiff图解法,综合分析各种地质因素,认为水文条件是该区块控气的主要因素,且水文地质控气存在着正负效应耦合的特殊性,合理分析水文地质特征是成功开采煤层气的关键所在.  相似文献   

Testing and evaluation of strength and deformation behaviour of jointed rocks     

《Geomechanics and Geoengineering》2013,8(2):149-158

The objective of the paper is to derive the strength and modulus properties of rockmass as a function of intact rock strength and joint factor. The joint factor reflects the combined effect of joint frequency, joint inclination and joint strength. A study for the strength and deformation characteristics of jointed rock is done by conducting standard laboratory tests on cylindrical specimens of plaster of Paris after introducing artificial joints. The specimens having one to four joints at different inclinations which vary from 0° to 90° were tested at different confining conditions. The test results were examined to understand the effect of joint frequency and joint inclination on the strength and deformation behaviour of rock mass. Empirical correlations were developed for prediction of the uniaxial compressive strength and elastic modulus of jointed rocks. Results are compared with the earlier work on jointed specimens covering a wide variety of rocks. So, knowing the intact rock properties and the joint factor, the jointed rock properties can be estimated. These relations can be used for developing an equivalent continuum model for rock mass for handling boundary value problems. A failure criterion as proposed by Ramamurthy (1993 Ramamurthy, T. 1993. “Strength and modulus response of anisotropic rocks”. In Comprehensive rock engineering, Edited by: Hudson, J.A. Vol. 1, 313–329. Oxford: Pergamon Press.  [Google Scholar]) has been validated from these experimental results.  相似文献   

Effect of shape on holding capacity of plate anchors buried in soft soil     

《Geomechanics and Geoengineering》2013,8(2):145-154

Plate anchor is one of the most common varieties of anchors used in the construction and maintenance work of various on-land and offshore structures. An accurate estimation of the uplift capacity of anchor foundations is necessary for an economical design as well as for the safety and stability of structures. This paper outlines the effect of shape of anchor plates on their breakout capacity, through a series of model tests. Both shallow and deep anchor behaviours were investigated under conditions developing suction force and without suction force. The results of these tests are presented in terms of load-displacement behaviour, variation of breakout factors (with and without suction force) with depth of embedment, the critical embedment depth of anchors and variation of suction force with embedment ratio. Further, the variations of breakout factor ratio with aspect ratio and embedment ratio are reported. Based on the experimental results and the model test results of other investigators an empirical relationship has been suggested to determine the shape factor and holding capacity of plate anchors buried in saturated cohesive soils.  相似文献   

四川康定捧塔乡金平电站滑坡成因分析     

孙逊  孟顺祥  王新杰  雷鸣  王营超 《四川地质学报》2013,(1):84-86

2010年6月14日23：30左右,四川省甘孜州康定捧塔乡金平电站施工现场在无征兆情况下突发了山体滑坡,致使临时施工营地工棚被掩埋,共造成23人死亡,7人受伤。通过对滑坡形成的地质条件分析,认为滑坡形成的山体斜坡的地形坡度42°～45°是控制滑坡形成的临空条件;滑坡松散体是滑坡形成的物质基础,致使滑坡滑动的诱发因素是连续强降雨。建议在地质灾害频发区实行资格准入和监测预警制度,避免滑坡、泥石流等地质灾害发生时致人群死群伤事件的发生。  相似文献   

高松山金矿床控矿因素及找矿模型     

冯志国  侯蕊娟 《四川地质学报》2013,(1):32-35

高松山金矿床位于伊春一延寿地槽褶皱系北段,是小兴安岭-张广才岭金及多金属成矿带中新发现的一个大型金矿床。文章从成矿地质背景、矿床地质特征等入手,分析了矿床的控矿因素,认为该矿床受地层、岩性、构造等因素控制;在综合研究的基础上,建立了高松山金矿综合找矿模型。  相似文献   

滇中地区铝土矿床地质特征及成矿规律     

梁秋原  刘文佳  王燕 《地球学报》2013,34(S1):163-167

通过对滇中地区典型铝土矿(老煤山铝土矿)成矿地质特征研究, 认为该区铝土矿为古风化壳沉积型铝土矿, 主要受地层层位、岩性古地理条件、褶皱构造及后期抬升改造影响。研究认为该区具有一定勘探潜力。  相似文献   

深层砂泥岩储层继承性裂缝发育特征     

张奎华  冯建伟  戴俊生 《地质力学学报》2013,19(2):214-224

西部挤压盆地内低渗性含油气砂泥岩储层构造运动期次多、埋藏深度大、泥质夹层多、高角度网状缝继承性发育,裂缝不仅是油气的有效运移通道,也是储层压裂开发效果的主要影响因素。选择西部天山山前某区块深层砂泥岩裂缝性气藏为研究区,以裂缝形成机制的探讨和研究为突破点,在岩心观察、CT层析成像扫描、成像测井解释的基础上,精细统计裂缝产状、开度、充填度,结合流体包裹体及古应力场划分裂缝发育期次,最后总结继承性裂缝的发育模式。研究结果表明,砂泥岩储层裂缝继承性缝的有利发育条件为多期次构造运动、低应力差、低逼近角度、适当泥质含量或低摩擦因数,岩性是内因,构造应力是外因。  相似文献   

气温变化对冬小麦生育的影响   总被引：5，自引：1，他引：5  

陈英慧宋建玉  房稳静 《河南气象》2003,(1):30-31

利用驻马店市1961年10月—2002年5月冬小麦生长季内平均气温资料以及气温5年滑动平均变化曲线图，采用相关分析法，分析了驻马店市冬小麦生长季内气温变化特征，并利用1981年以后的冬小麦作物观测资料，经过对比分析，揭示了冬小麦生长发育过程中因暖温而产生的一系列变化。  相似文献   

河南省春季气候变化及其对小麦产量构成要素的影响   总被引：4，自引：0，他引：4  

陈怀亮张雪芬  赵国强刘伟昌 余卫东 《河南气象》2006,(1):47-52

目前有关气候变化及其对农作物产量影响的研究较多,而对产量构成要素的影响研究相对较少。本文利用自然正交函数(EOF)分解、相关分析、趋势倾向率分析等方法对河南省近30多年的气候和近20多年的小麦产量构成三要素———穗数、粒数、粒重进行了时空变化特征分析,在此基础上分析了春季气候变化对小麦产量及其构成要素的影响。结果表明:全省春季平均气温、降水量、日照时数变化具有比较好的空间一致性,平均气温呈比较明显的上升趋势,降水呈不太明显的下降趋势,日照呈一定的下降趋势;小麦粒重和产量变化具有较好的空间一致性,而穗数、粒数则具有反位相空间变化特征,穗数、粒重及产量均呈明显的上升趋势,粒数呈抛物线变化趋势,其中1991年后呈明显上升趋势;平均气温的升温变化趋势有利于小麦粒重、穗数和最终产量的提高,但不利于粒数增加;降水变化趋势不利于粒重提高,对其他产量构成要素影响不明显;日照的变化对产量及各构成要素影响不明显。  相似文献