基于热力学基础上的非饱和砂土本构模型-理论研究     

张卫华  赵成刚  郜新军  董晓丽 《工程地质学报》2014,22(6):1094-1101

热力学是一种普适理论,因此非饱和砂土的变化过程必然也遵循热力学原理。利用热力学原理可以从更普遍的情况(条件)和更一般的视角审视非饱和土的水力-力学性质。本文基于热力学理论并考虑砂土的剪胀-各向异性以及塑性耗散之间的关系,建立固-液两相耦合的非饱和砂土本构模型的理论框架,更深入地揭示非饱和砂土复杂的行为和性质。  相似文献   

东帝汶帝力市珊瑚砂地基的工程性质     

唐国艺  夏玉云  刘争宏 《岩土工程技术》2013,(5):248-251

珊瑚砂属珊瑚礁碎屑土,是一种特殊的地质体,具有典型的疏松多孔、硬度低、易碎的特点,由于珊瑚礁仅分布在热带海域,往往位于远离大陆的礁岛,当前对珊瑚礁岩土的勘察研究较少,相关规范也尚未涉及。以实际工程为对象,对东帝汶某珊瑚砂场地的工程性质进行了一些探讨,从标准贯人试验和钻孔剪切波速试验等原位试验结果进行分析,借鉴了目前石英砂工程性质的评价方法作为对珊瑚砂工程性质判断的参考,对珊瑚砂的强度特性和地震液化特性进行了讨论。相对石英砂的一般性质而言,珊瑚砂的标贯击数较低而相应的剪切波速相对较大,珊瑚砂在地震作用下液化的可能性较大。  相似文献   

准噶尔盆地西北缘风城油砂分布特征及成矿条件   总被引：1，自引：0，他引：1  

郝玉鸿  张银德  周文  梁亚军  姜有才 《物探化探计算技术》2013,(6):675-682

准噶尔盆地西北缘风城地区蕴含着丰富的油砂资源,地表出露油砂形成多座规模不等的油砂山丘,面积约8km2,油砂主要存在于白垩系吐谷鲁组,连片集中、厚度大。风城下伏地层油砂分布面积大,层位稳定,产状缓,也主要分布在白垩统吐谷鲁组、上侏罗统齐古组中,含油率高、油质较好。该区油砂资源主要来源于玛纳斯湖凹陷二叠系烃源岩,这套烃源岩中生成的油气沿着该地区发育的断裂和不整合面向上运聚。断裂、不整合面及砂体的分布叠置构成了运移系统,有效的砂体既是运移通道又是储集体,最后建立了该区远源次生的油砂成矿模式。  相似文献   

近50年黄河乌兰布和沙漠段辫状河道演变   总被引：4，自引：3，他引：1  

李永山  彭文昌  任亮  李勇 《中国沙漠》2016,36(6):1689-1694

依据水沙资料和断面资料,对黄河乌兰布和沙漠段辫状河道形态近50年演变特征及趋势进行探讨分析。结果表明：在大流量条件下（1966-1993年）,河流横向侵蚀、搬运堆积过程强烈,风沙入黄（河）量大,河道横向摆动频繁,辫状河道发育强烈。当黄河流量减小时（1993-2013年）,河流横向摆动能力减弱,黄河主河槽远离左岸乌兰布和沙漠沙丘,河流输沙能力减弱,汊道泥沙淤积导致心滩边滩相连,河流分汊数量明显减少,辫状河道萎缩,黄河乌兰布和沙漠段辫状河型有向弯曲型河道转变的趋势。  相似文献   

骨架导电的混合泥质砂岩通用孔隙结合电阻率模型研究   总被引：15，自引：9，他引：6       下载免费PDF全文

宋延杰  王秀明  卢双舫 《地球物理学进展》2005,20(3):747-756

在水介质中顺序添加分散粘土颗粒、油珠、导电骨架颗粒、层状泥质,并对每一种成分进行连续积分,建立了一种适用骨架导电及含有分散粘土和层状泥质的泥质砂岩通用电阻率模型.通过对该模型的影响因素分析,发现泥质分布形式对模型计算的含水饱和度有很大影响;对应两个不同粘土颗粒电阻率或骨架颗粒电阻率的地层电导率之差,几乎与总含水饱和度无关,而对应两个不同层状泥质电阻率的地层电导率之差,随总含水饱和度增大而增大;骨架胶结指数变化对地层电导率与总含水饱和度关系曲线的影响最大,而粘土胶结指数变化对地层电导率与总含水饱和度关系曲线的影响最小;饱和度指数对地层电导率与总含水饱和度关系曲线的影响随总含水饱和度的增大而减小.通过一组骨架导电的人造岩样的试验,表明当地层水电阻率.小于颗粒电阻率时,该模型可以用于不含粘土的骨架导电的岩石.通过两组分散泥质砂岩岩样实验测量数据和一组层状泥质砂岩测井资料及实际测井资料的计算,表明本文给出的电阻率模型既适用于分散泥质砂岩地层解释又适用于层状泥质砂岩地层解释,同时,还适用于含有分散粘土和层状泥质的混合泥质砂岩地层解释.  相似文献   

Heavy Minerals and Rare Earth Elements in Coastal and Inland Dune Sands of El Vizcaino Desert,Baja California Peninsula,Mexico     

J. J. Kasper-Zubillaga  A. Carranza-Edwards  O. Morton-Bermea 《Marine Georesources & Geotechnology》2013,31(3):172-188

A heavy mineral (HM) study and light and heavy rare earth elements (LREE and HREE) analysis were performed in coastal and inland dune sands, El Vizcaino Desert, Central Baja California Peninsula, Mexico. Our study shows high abundances of hornblende and apatite in the El Vizcaino dune sands, suggesting a dominance of granodiorites/intermediate plutonic rocks and marine authigenic phosphorite in the dune sands. There is a relationship between unstable heavy minerals like hornblende, pyroxenes, and sphene, and heavy rare earth elements (HREE) that suggests that unstable heavy minerals are potential carriers of HREE in the dune fields. However, there is a slight depletion of HREE in relation to LREE, especially in one locality of the inland dunes probably associated with the wind regime and weathering of unstable heavy minerals in the sands. Inland, transitional, and coastal dune fields can be observed as different dune provinces by means of grouping HM and REE data in two separate dendograms. It seems that HREE are correlated with fine-grained sand sizes and correlated with high CIA values linked to slightly weathered sands.  相似文献   

Biogrouting of hydraulic fill fine sands for reclamation projects     

Jijian Lian  Hongyin Xu  Xiaoqing He  Dengfeng Fu  Shuwang Yan 《Marine Georesources & Geotechnology》2013,31(2):212-222

ABSTRACT

Biogrouting, which is a new method for soil improvement, was used in an attempt to cement a type of hydraulic fill fine sands (called black sands) in reclamation projects in Tianjin, China, to form a working layer for mechanical equipment. Several factors influencing biogrouting with regard to cementing solution, including injection frequency, reaction time, concentration, and flow rate, were controlled to prepare black sand columns. This paper reports on an investigation of bacterial fixation, calcium ion utilization, and calcium carbonate distributions of biogrouted sand specimens. At the end of the tests, the geotechnical performances of the sand specimens were determined. The results showed that the biogrouting method effectively solidified black sands, by increasing the unconfined compressive strength of a sand column to 1.91?MPa and reducing the permeability coefficient by three orders of magnitude. A relationship between the unconfined compressive strengths and calcium carbonate contents was put forward, in addition to a relationship between the permeability coefficients and the calcium carbonate contents. According to the experimental results, some reasonable suggestions regarding the application of biogrouting to the consolidation of hydraulic fill fine sands in reclamation projects were proposed.  相似文献   

The critical state and steady state of sand: A literature review     

Xin Kang  Renpeng Chen  Louis Ge  Xiaoming Liu 《Marine Georesources & Geotechnology》2013,31(9):1105-1118

Abstract

The critical state and steady state theories are widely accepted for simulating the soil behavior and providing a basis for liquefaction evaluation and constitutive modeling. However, there was conflicting evidence regarding the critical state and steady state of sands in the last decades. In some cases, the critical state and steady state are taken to be identical and in others they differ significantly. Whether they are the same or not remain a hot academic debate to date. This paper provides a critical review on the origin and history of the critical state and steady state of sands, which identifies conflicting evidences and discusses the influencing factors on the existence and uniqueness of critical state and steady state. Based on a critical review of literature, it is concluded that the steady state concept is a refinement of the critical state concept and the uniqueness of the critical state and steady state was affirmed. Special care should be paid in the laboratory techniques in order to accurately measure the critical state and steady state due to the numerous influencing factors of them.  相似文献   

基于TM图像的潮滩表层沉积物含水量推算模型研究——以江苏辐射沙洲区为例     

沈永明  杨劲松  张忍顺  刘咏梅 《地理科学》2009,29(3)

潮滩表层沉积物含水量是反映潮滩与潮水周期性作用并指示潮滩高程的重要指标,了解潮滩表层沉积物含水量是开发利用潮滩资源的重要工作之一。以江苏辐射沙洲为例,在对应于2000年4月的TM遥感图像成像时潮位特征的潮汐周期时,测量了两条断面的表层沉积物含水量,然后通过对辐射沙洲TM遥感图像的多种处理及其比较,找出了TM图像与潮滩表层沉积物含水量的相关系数绝对值最高的数字图像处理方法,然后再进行傅立叶变换等处理,并推算出可决系数较高的表层沉积物含水量推算模型。  相似文献   

油砂组分遥感光谱响应特征及意义          下载免费PDF全文

尤金凤  邢立新  潘军  单玄龙  樊瑞雪 《地球物理学报》2016,59(8):3068-3078

基于油砂组分的吸收光谱物理响应机理,通过对比矿物基团平均吸收深度,建立主要蚀变矿物ASTER多光谱遥感数据异常提取模式以识别油砂分布.研究表明,与传统的烃类微渗漏遥感研究手段相比,该模式可以更有效地指示油砂的分布.利用油砂组分基团光谱平均吸收深度与孔隙度及渗透率进行相关分析,研究了油砂光谱与所处地质背景环境中储层物性之间的关联关系.结果表明,表征粘土矿物含量的粘土基团吸收深度与孔渗值呈负相关关系,指示含油性的烃类基团吸收深度与孔渗值呈显著正相关关系.  相似文献