Leachate studies on fly ash-stabilised expansive clay liners

This paper presents leachate studies on fly ash-stabilised expansive clay liners. Fly ash in different contents (0%, 10%, 20% and 30%) by dry weight of the expansive clay was added to the clay, and the ash-clay blend was compacted as a liner overlying a compacted lateritic clay layer. Deionised water (DIW) and calcium chloride (CaCl₂) solutions of varying concentration (5 mM, 10 mM, 20 mM, 50 mM, 100 mM and 500 mM) were used as the permeating fluids in the leachate studies. Chemical analysis of the leachate was performed. For a given CaCl₂ concentration, the concentrations of both calcium ion and chloride ion in the leachate decreased up to a fly ash content of 20%, and thereafter they increased when the fly ash content was increased to 30%. Further, for a given fly ash content, concentrations of calcium ion and chloride ion increased with increasing CaCl₂ concentration.     

Geotechnical Hybrid Simulation to Investigate the Effects of the Hydraulic Conductivity on One-Dimensional Consolidation Settlement

Difficulties in the prediction of time-distribution of consolidation settlement will be introduced by using the Murayama test embankment case of Japan. In particular, it will be discussed why the prediction of consolidation rate is difficult in multi-layered soil with complex and variable mechanical properties like organic soil or peat. It can be inferred that uncertainties, which are embedded intricately in the consolidation problem as well as given ground condition, would be major causes for consolidation settlement. After that, the author focused on the movement of pore water under the various conditions of hydraulic conductivity in the soils, and how it can affect the time-distribution of the consolidation settlement. For the applied key methodology on the consolidation settlement problem, we propose the hybrid consolidation simulation controlling the movement of pore water with high accuracy and, finally, the aim of this article is to discuss the methodological approaches obtained by the study, including the basic concept and accurate movement of pore water under various conditions of soil layers and hydraulic conductivity.     

Numerical Analysis of Gravity Coring Using Coupled Eulerian-Lagrangian Method and a New Corer

The shortcomings of gravity corers in sampling marine sediments have been observed extensively in various field tests. In order to optimize the coring, this article provides an alternative numerical way to model the gravity coring and analyze the sampling effect. Based on this analysis, a new hydraulic hammer corer is devised. A coupled Eulerian-Lagrangian method with capability of simulating the problem involving extreme deformation, penetration is used to simulate the coring process. The results show that the hydrostatic pressure and deviator stress increase and reach their peak when the pile tip is slightly above or at the level of the observation point and then drop rapidly when the pile tip slides below the observation point. In addition, the stress path indicates that the soil element sustains plastic compression before yielding and then expands until recovering to the original state. The obvious “under-sampling” phenomenon is also well-captured by the finite element model.     

Is Ziarat a Potential Site for Conventional or Unconventional Energy Resources?

A structural interpretation of the Ziarat block in the Balochistan region (a part of the Suleiman Fold and Thrust Belt) has been carried out using seismic and seismological data. Seismic data consists of nine 2.5D pre‐stack migrated seismic lines, whereas the seismological data covers the Fault Plane Solution and source parameters. Structural interpretation describes two broad fault sets of fore and back thrusts in the study area that have resulted in the development of pop‐up structures, accountable for the structural traps and seismicity pattern in terms of seismic hazard. Seismic interpretation includes time and depth contour maps of the Dungan Formation and Ranikot group, while seismological interpretation includes Fault Plane Solution, that is correlated with a geological and structural map of the area for the interpretation of the nature of the subsurface faults. Principal stresses are also estimated for the Ranikot group and Dungan Formation. In order to calculate anisotropic elastic properties, the parameters of the rock strength of the formations are first determined from seismic data, along with the dominant stresses (vertical, minimum horizontal, and maximum horizontal). The differential ratio of the maximum and minimum horizontal stresses is obtained to indicate optimal zones for hydraulic fracturing, and to assess the potential for geothermal energy reservoir prospect generation. The stress maps indicate high values towards the deeper part of the horizon, and low towards the shallower part, attributed to the lithological and structural variation in the area. Outcomes of structural interpretation indicate a good correlation of structure and tectonics from both seismological and seismic methods.     

FD-600全液压动力头反循环连续取样钻机研制与应用

文章结合国内外CSR取心技术的现状和所生产钻机的特点,为满足国内对空气反循环连续取样（心）、冲击回转、定向钻进等多种高效钻探工艺对钻机的需要,从钻机整体结构设计、整体布局进行详细考量,采用质量可靠的液压件、动力机等外购件,摒弃传统钻机设计周期长、动力小、机械化程度低、对地形和钻探工艺适应性低等特点,研制出了一台高效、可靠、机械化程度较高的FD-600型全液压动力头式反循环取样钻机。在3次野外生产试验中充分体现出了优越性,可满足砂金勘探、工程施工等取心钻探的要求。     

极地深部冰层取心钻探孔壁水压致裂研究

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。     

四川平武银厂金矿勘探复杂地层钻进技术

四川平武银厂金矿区钻探施工中遇到漏失、缩径、岩心破碎、易孔斜和钻孔事故频发等施工难题,施工难度极大。本文结合地层特点,通过采用绳索取心液动锤、高密度低失水泥浆体系、跟管钻进等工艺技术措施,提高了钻进效率和施工质量,大幅度减少了孔内事故的发生,为顺利完成钻孔施工任务奠定了坚实的基础。     

福建霞浦大湾钼铍矿区碱长花岗岩LA-ICP-MS锆石U-Pb测年研究

福建霞浦大湾钼铍矿床产于火山岩区,但成矿作用可能与岩浆活动和裂隙构造关系密切。为查清矿区隐伏的钠长石化碱长花岗岩与钼铍矿成矿作用之间的关系,本文运用激光剥蚀电感耦合等离子体质谱法(LA-ICP-MS)对碱长花岗岩进行锆石U-Pb测年研究,获得年龄结果为93. 0±0. 6 Ma,与矿区的辉钼矿成矿年龄(92. 2±1. 3 Ma)一致,表明碱长花岗岩与钼铍矿成矿作用时空上具有密切的成因联系,岩浆活动可能为矿区钼铍矿的形成提供了成矿物质和成矿流体。结合区域上的成岩成矿年代学数据,本研究认为福建省燕山期岩浆活动时代与钼铍矿成矿时代都具有从西向东逐渐变新的时空分布规律,钼铍矿的成矿地质构造背景为燕山期华南岩石圈伸展环境。     

湖南仁里稀有金属矿田36号伟晶岩地球化学特征、成矿时代及其意义

位于幕阜山岩体西南缘的仁里稀有金属矿田是近年来华南地区新发现的一处重要花岗伟晶岩型稀有金属矿产地,铌钽矿体赋存于岩体内外接触带伟晶岩中,具有明显成矿分带性.文章选取仁里矿床岩体内接触带36号伟晶岩脉为研究对象,开展伟晶岩的地球化学及云母Ar-Ar年代学研究,探讨其与花岗岩围岩成因关系及岩体内接触带伟晶岩的成岩成矿时代,以丰富仁里矿田稀有金属成矿作用研究.研究表明,36号伟晶岩具高硅(w(SiO2)为72.87％～76.21％)、高铝(w(Al2O3)为13.69％～15.14％)、低钙镁铁、相对富碱(w(Na2O+K2O)为6.59％～8.33％)、(高钾)钙碱性及过铝质特征;微量元素总体富集Nb、Ta、Hf、U等高场强元素(HFSE),相对亏损Ba、Sr等离子亲石元素(LILE);稀土元素总量(ΣREE)13.95×10-6～71.63×10-6,轻稀土元素富集,重稀土元素亏损,具壳源特征.白云母Ar-Ar坪年龄为早白垩世(136.6±1.4)Ma,成矿作用发生于仁里矿田稀有金属大规模成矿的早阶段.地球化学及矿物学特征显示,36号伟晶岩与花岗岩围岩具有良好的演化关系,结合野外观察现象及成岩年龄,认为36号伟晶岩为花岗质岩浆侵位后残余岩浆结晶分异的产物,母岩为中粗粒片麻状黑云母二长花岗岩.     

老盐井组井型互换再利用工程实践

水平钻井连通水溶采卤一直是开采井矿盐资源最常用和最经济有效的手段,但由于地层条件复杂、饱和卤水结晶、套管破损等因素造成盐井组采卤运行过程中通道堵塞,一直是制约盐井组运行年限的主要原因。近些年,对堵塞井组修治常用方法有憋压、通井、开窗侧钻,其中水平井开窗侧钻重新对接现有溶腔在很多盐田区块修井中被广泛应用。在河北宁晋石盐田Y2-Y4井组修井过程中,存在老溶腔无法再利用的情况,此时老溶腔成为井组二次对接的“累赘”。在该区块首次采用井组井型互换（水平井改直井,直井改水平井）的方法,避开了老溶腔,实现了老井组的再利用。