Effects of Mudstone Particle Content on Shear Strength of a Crushed Sandstone–Mudstone Particle Mixture     

Jun-Jie Wang  Zhen-Feng Qiu  Wen-Jie Deng  Hui-Ping Zhang 《Marine Georesources & Geotechnology》2016,34(4):395-402

The present study focuses on the shear strength, deformation, and particle crushing of sand which is mixed by crushed sandstone and mudstone particles. Two triaxial tests—one for unsaturated specimens and the other for saturated specimens—were performed, along with sieve analysis tests. Results obtained from the triaxial tests indicate that, with the increment of the mudstone particle content by weight, the angle of internal friction decreases, the cohesion increases and then decreases, and both the initial angle of shearing resistance at the atmospheric pressure and decremental angle increase and then decrease. Compared to the unsaturated specimens, the deviator stress or normalized deviator stress of the saturated specimens at the same axial stress may decrease due to the wetting action. Thus, the shear strength of the tested materials may be reduced by the wetting action. Results of sieve analysis tests indicate that the mixing of some mudstone particles into the sandstone particle mixture may reduce the amount of particle crushing, but the wetting action may increase the amount. The amount of the crushed particle may arrive at a minimum of 40% of mudstone particle content by weight.  相似文献   

Laboratory Study for Influence of Clay Content (CC) on Wave-Induced Liquefaction in Marine Sediments     

B. Liu 《Marine Georesources & Geotechnology》2016,34(3):280-292

In this artice, the influence of clay content on the wave-induced liquefaction in marine sediments was reported. The one-dimensional (1-D) equipment was setup with a vertical cylinder and 1.8–m–thick clayey sandy deposit and 0.2–m–thick water above the deposit. Unlike the previous experimental study for a single soil layer, this study used sand-kaolin mixtures, sand-illite mixtures, and sand-bentonite mixtures as the experimental samples. A series of experiments with 3,000 wave cycles in each test were conducted under numerous wave and soil conditions, which allowed us to examine the influence of clay content (CC) on wave-induced liquefaction in marine sediments. The experimental results showed that the clayey sandy deposit will become prone to liquefaction with the increase of CC when CC is less than a critical value, which depends on the type of clay. However, when CC is greater than the critical value, liquefaction depth will decrease as CC increases. Furthermore, when the CC value reaches a certain level, liquefaction will not occur. For example, no liquefaction occurs when CC ≥ 33% for both kaolin-sand and illite-sand mixtures and CC ≥ 16.36% for bentonite-sand mixtures.  相似文献   

Comparative Study of Hydrogen and Carbon Isotopic Composition of Gases Generated from the Pyrolysis of a Peat under Saltwater and Freshwater Conditions     

WU Yingzhong  DUAN Yi  ZHAO Yang  CAO Xixi  MA Lanhu  QIAN Yaorong  LI Zhongping  XING Lantian 《《地质学报》英文版》2018,92(5):1879-1887

To understand the influence of the diagenetic water medium on the isotopic compositions of thermogenic coalbed gas, both hydrous and anhydrous closed-system pyrolyses were performed at temperatures of 250°C to 650°C on an herbaceous marsh peat. Compared to the results of anhydrous pyrolysis, the hydrocarbon gases generated from hydrous pyrolyses have very different hydrogen isotopic compositions. However, the carbon isotopic compositions of the hydrocarbon gases became only slightly heavier in hydrous pyrolysis, compared to that from anhydrous pyrolysis. With the progress of thermal evolution from peat to a more advanced thermal maturity of vitrinite reflectance values (Ro) of 5.5% during the pyrolysis, the difference in the average δD value increased from 52‰ to 64‰ between the hydrous pyrolysis with saltwater and anhydrous pyrolysis and increased from 18‰ to 29‰ between the hydrous pyrolysis with freshwater and anhydrous pyrolysis, respectively. The difference in the average δ13C value was only 1‰–2‰ between the hydrous and anhydrous pyrolysis. The relationships between the δD values of the generated hydrocarbon gases and Ro values as well as among δD values of the hydrocarbon gas species are established. The close relationships among these parameters suggest that the water medium had a significant effect on the hydrogen isotopic composition and a minimal effect on the carbon isotopic composition of the hydrocarbon gases. The results of these pyrolyses may provide information for the understanding of the genesis of coalbed gas from herbaceous marsh material with the participation of different diagenetic water media.  相似文献   

极地深部冰层取心钻探孔壁水压致裂研究          下载免费PDF全文

张晗  陈晨  Pavel Talalay  毛建设  刘书源  靳成才  宛召 《探矿工程》2018,45(11):5-11

为了维护极地深部冰层取心钻探工作中钻孔的稳定,避免孔内事故的发生,冰层孔壁的水压致裂问题是亟待解决的重要科学问题之一。本文在深入分析国内外冰层钻探资料的基础上,结合冰盖动力学相关理论,计算得出了钻孔所在区域冰层的密度、温度及内部应力随深度的变化规律。在此基础上,结合油气资源勘探水力压裂技术与冰层钻进钻井液等相关理论,建立了合理的孔壁压差计算方法,深入探讨了适用于深部冰层钻探孔壁水压致裂机理。研制了冰层钻孔水压致裂模拟实验装置,可分析研究不同围压条件下冰样的脆性变形机理。结合我国Dome A深冰心钻探工程实际,提出钻孔可能发生水压致裂的深度区域及孔壁所需的起始裂纹长度判定,以期为后续的安全高效冰层钻进提供重要的理论依据。  相似文献   

蒙脱石伊利石化的水热实验模拟     

张俊程  李本仙  孟杰  李耀宗  王晓峰  刘晓旸  施伟光 《世界地质》2018,37(1):316-326

以蒙脱石为初始材料,通过水热实验模拟在不同温度压力条件下蒙脱石的伊利石化过程。利用X射线粉末衍射及X射线荧光光谱、红外光谱和扫描电镜等方法对样品的矿物物相、化学成分、晶体结构与微观形貌等进行分析,其结果表明:(1)蒙脱石至伊利石的转化受温度和压力条件的控制;(2)随着温度和压力的增高,蒙脱石伊利石化沿着蒙脱石-无序伊蒙混层-有序伊蒙混层-伊利石的转化序列进行转化;(3)水热实验模拟表明蒙脱石至伊利石的转化以溶解重结晶机制为主。实验结果不仅有助于了解埋藏与低级变质作用中的蒙脱石伊利石化过程,同时为研究断层活动所致断层泥中黏土矿物的转化及反演断层形成时温度压力条件提供基本参数。  相似文献   

土壤入渗对阜新市北部浅层地下水总硬度影响的淋滤实验     

陈建平  吕相伟  邱岩  董军 《世界地质》2018,37(4):1295-1300

本次室内土柱淋滤实验通过改变Na~+、H~+、NH_4~+浓度来模拟现实生活中不同浓度的生活污水、酸雨及农业施肥灌溉对浅层地下水总硬度的影响过程。实验结果表明淋滤液浓度越高,所对应的淋出液的总硬度峰值就越高。相同浓度的Na~+、H~+、NH_4~+进行土柱淋滤实验时,NH_4~+所对应的淋出液总硬度的峰值最大,H~+次之,Na~+最小且NH_4~+所对应的整个实验用时最短,在相同浓度单一离子作用下NH_4~+对浅层地下水硬度的影响更加明显。  相似文献   

北大西洋地区气候准20年周期的观测和模拟分析          下载免费PDF全文

傅心雨  陶丽 《大气科学学报》2021,44(6):938-944

北大西洋地区除了存在约70 a周期的AMO（Atlantic Multidecadal Oscillation,北大西洋年代际振荡）之外,历史长期气候记录中英格兰温度（Central England Temperature,CET）与格陵兰冰芯净雪累计率还存在显著的20 a周期波动。本研究利用CCSM4（Community Climate System Model version 4）耦合模式工业革命前控制试验（piControl）结果中的海表面温度（Sea Surface Temperature,SST）,通过10～50 a带通滤波与扩展经验正交函数（Extended Empirical Orthogonal Function,EEOF）分解,得到在北大西洋副极地海区存在准20 a振荡的逆时针旋转模态。此周期与其临近地区的CET、格陵兰冰芯净雪累计率的准20 a振荡周期相吻合,说明这种北大西洋副极地海区准20 a振荡的海洋模态与其临近地区的大气准20 a振荡之间可能存在相应的联系。进一步利用CAM4（the Community Atmosphere Model version4）大气模式,以北大西洋副极地海区准20 a振荡SST旋转模态为强迫场进行敏感性试验,进一步验证了这种联系。  相似文献   

协调大集合模拟下全球海表面温度对北极对流层早冬增暖的影响          下载免费PDF全文

Lutao Wang  Yongqi Gao  Dong Guo  Tao Wang  Ying Zhang  Wei Hua 《大气和海洋科学快报》2021,14(1):57-62

本文使用六个不同的最新大气模式进行了协调数值集合实验,评估和量化了全球海表面温度(SST)对1982-2014年冬季早期北极变暖的影响.本研究设计了两组实验:在第一组(EXP1)中,将OISSTv2逐日变化的海冰密集度和SST数据作为下边界强迫场;在第二组(EXP2)中,将逐日变化的SST数据替换为逐日气候态.结果表明:(1)EXP1的多模式集合总体平均值显示0.4℃/10年的近地表(约850 hPa)升温趋势,为再分析数据结果中升温趋势的80％.(2)在这六个模式中,模拟的变暖趋势均很强,幅度为0.36-0.50℃/10年.(3)全球海表温度可以解释北极对流层中低层EXP1的大部分模拟的变暖趋势,占再分析数据结果的58％.(4)再分析数据结果中,北极上空的对流层上层变暖(约200 hPa)不是由强迫信号而可能是由自然气候变率引起的.本文还探索了影响北极初冬变暖的可能源区,并讨论了该研究的局限性.  相似文献   

高压电脉冲破岩试验装置的研制          下载免费PDF全文

梁丽  肖一标  李大鹏  段隆臣  张锋  李昌平 《探矿工程》2021,48(11):77-83

高压电脉冲破岩钻进在国际上被认为是一种在深部钻探中具有广阔发展前景的破岩方法,但在国内研究还很少。本文设计制造了一套高压电脉冲破岩试验装置,包含伺服电动缸、控制柜、岩石容器等部件,试验装置配套了?60 mm和?100 mm的电脉冲钻头,可选择手动或自动加压放电破碎岩石。在放电电压为120 kV、放电频率为1 Hz的条件下进行了红砂岩等岩石的钻进试验,实现了60 mm口径的钻进碎岩。试验结果表明,该装置能满足电脉冲破岩试验的基本要求,可用于电脉冲碎岩室内研究。  相似文献   

高温与冻融循环对水热炭和生物炭吸附污染物的影响     

关俊杰  刘雨嫣  刘思源  陈家玮 《现代地质》2021,35(4):931-939

将农林废弃物通过不同碳化方式制备成水热炭或生物炭,用于土壤改良和环境污染修复,是当前研究和应用的热点领域。由于受到不同自然条件的长期影响,如环境温度变化,水热炭和生物炭会发生老化作用,从而影响其对污染物的吸附能力,因此,评估老化作用对碳化材料吸附能力的影响是一个重要的科学问题。采用高温和冻融循环2种加速老化方式模拟自然界中的温度变化,对稻壳和玉米秸秆水热炭、生物炭进行老化培养,通过元素分析仪、傅里叶红外光谱分析仪、扫描电子显微镜等手段对老化前后水热炭、生物炭样品的物化性质进行分析,通过批实验对比研究2种新鲜炭材料对Cd(II)及莠去津的吸附能力及吸附稳定性,并研究了30、60、90次老化循环后生物炭和水热炭吸附能力的变化。结果表明,生物炭对Cd(II)和莠去津有良好的吸附稳定性,而水热炭对莠去津的吸附稳定性较差。2种老化作用均使水热炭、生物炭表面含氧官能团增加,从而增强了水热炭、生物炭对Cd(II)和莠去津的吸附能力。在高温和冻融环境中,随着老化时间的持续,生物炭比水热炭更容易受到环境的影响。研究相关成果对于水热炭和生物炭合理应用于不同环境的污染修复具有试验参考价值。  相似文献