Evaluation of three waterborne polymers as stabilizers for sandy soil

This study reports on waterborne polymer emulsion systems that were used for structural modification of sandy soils. The first emulsion used was a styrene-acrylic, copolymer emulsion; the second and third were vinyl-acrylic, copolymer-based emulsions. Specimens were prepared by adding different polymer emulsions to the sand and water in prescribed amounts. The performance of the different emulsion systems as sand stabilizers was estimated through measurement of the hydraulic conductivity and compressive strength. Measurements of hydraulic conductivity were conducted in a flexible membrane test apparatus. The hydraulic conductivity for the three emulsions decreased at different rates, with an increase in polymer content up to 3 wt. (i.e., % by weight). Additional increase of polymer content did not introduce significant decrease in hydraulic conductivity, and, at 5 wt.%, the three emulsions had essentially the same effect. Measurements made on dry cylindrical specimens disclosed remarkable enhancement in the mechanical behavior of the system. The compressive strength and modulus of elasticity of the examined emulsions increased with a higher concentration of polymer. Scanning electron microscope (SEM) revealed that the reduction in the permeability and the improved mechanical properties can be attributed to three dominant structural changes: the development of interconnecting ties between the sand particles, the development of adhesion between neighboring sand particles in contact, and the covering of the sand particles with a thin polymer film.     

压裂井经济分析的优化方法

水力压裂是油气井增产的一项重要技术措施。压裂效果的经济评价，实际上是一个压裂设计的优化过程。研究经济问题即为研究压裂优化问题。提出了压裂井的施工费用计算方法和贴现率、净收入、净现值的计算公式，并对压裂井进行了经济分析，给出了压裂设计优化的步骤。建立了八屋—后五家户气田压裂经济评价模型，并应用到实际施工现场。使油气单井产量比过去增加2～3倍。     

闽西北地区隐爆作用与火山岩型铀矿化

隐爆角砾岩体对火山岩型铀矿化的控制作用已为实践所证明，并引起高度重视。本文阐述了闽西北地区隐爆角砾岩形成的时空条件、与围岩的关系、分带性及其鉴别要素。以实例说明隐爆角砾岩体对铀矿化起控制作用的３种主要形式，指出了寻找隐爆角砾岩体的方法。     

Channel adjustments of the lower Trinity River,Texas, downstream of Livingston Dam

Channel cross‐sectional changes since construction of Livingston Dam and Lake Livingston in 1968 were studied in the lower Trinity River, Texas, to test theoretical models of channel adjustment, and to determine controls on the spatial extent of channel response. High and average flows were not significantly modified by the dam, but sediment transport is greatly reduced. The study is treated as an opportunistic experiment to examine the effects of a reduction in sediment supply when discharge regime is unchanged. Channel scour is evident for about 60 km downstream, and the general phenomena of incision, widening, coarsening of channel sediment and a decrease in channel slope are successfully predicted, in a qualitative sense, by standard models of channel response. However, there is no consistent channel response within this reach, as various qualitatively different combinations of increases, decreases or no change in width, depth, slope and roughness occur. These multiple modes of adjustment are predicted by the unstable hydraulic geometry model. Between about 60 km and the Trinity delta 175 km downstream of the dam, no morphological response to the dam is observed. Rather than a diminution of the dam's effects on fluvial processes, this is due to a fundamental change in controls of the fluvial system. The downstream end of the scour zone corresponds to the upstream extent of channel response to Holocene sea level rise. Beyond 60 km downstream, the Trinity River is characterized by extensive sediment storage and reduced conveyance capacity, so that even after dam construction sediment supply still exceeds transport capacity. The channel bed of much of this reach is near or below sea level, so that sea level rise and backwater effects from the estuary are more important controls on the fluvial system than upstream inputs. Copyright © 2005 John Wiley & Sons, Ltd.     

相山铀矿田巴泉隐爆角砾岩(筒)地质特征与铀成矿

巴泉铀矿床位于相山矿田的北部边缘,是典型的隐爆角砾岩(筒)型铀矿床。隐爆角砾岩(筒)是由与相山火山机构有密切联系的燕山晚期侵入于震旦系变质岩中的潜花岗斑岩岩枝发生隐爆作用而生成。矿床是多阶段岩浆活动、多次隐爆作用和多期铀成矿作用互为响应、连续发展地质过程的产物,是集岩浆岩体-角砾岩体-铀矿体为一体的综合地质单元。燕山晚期潜花岗斑岩浆和英安玢岩浆的侵入、隐爆作用形成的角砾岩(筒),以及断裂构造的频繁运动,对铀成矿乃至矿床的形态和规模起到重要的控制作用。隐爆角砾岩(筒)的形成具有脉动性、隐爆性,显示隐爆角砾岩岩性的复杂多变,矿化蚀变种类、组合和强弱变化具有规律性。铀矿体(化)主要赋存于隐爆角砾岩和震碎角砾岩中,矿化显现出中富边贫、上强下弱的特征。     

陕西太白双王角砾岩型金矿的角砾岩特征

双王金矿床是秦岭泥盆系地层中一种类型独特富钠角砾岩型金矿床,在分析研究矿床赋矿地层、角砾岩带、角砾岩体的矿化及分带特征的基础上,阐述了该矿床的分带特征与金矿化的关系。     

地质钻探技术与应用研究

钻探技术是取得地下实物资料、验证地下信息推断与解释、最终圈定矿体、计算储量、评估品位唯一的技术手段,是实现取得宏观影响大成果的重要技术支撑.我国钻探技术和装备水平与国外先进国家相比有很大的差距,但近些年来有了长足的发展.通过国家重大科学工程项目“中国大陆科学钻探工程”5158m“科钻一井”的实施,取得了一系列钻探技术成...     

多孔介质渗透系数的空间尺度效应研究进展

多孔介质渗透系数的空间尺度问题是一个与地下流体运动和溶质运移的数值模拟密切相关的应用性课题,广泛的应用需求和新的计算方法使其成为近年的热门课题之一。它涉及到相互联系的两个方面：①非均质介质场渗透系数空间尺度行为的分析与模拟;②将局部测量尺度下的试验参数转化为数值模拟网格尺度下的参数输入值的升尺度（ｕｐｓｃａｌｉｎｇ）方法和计算模型。首先介绍了该课题在概念上的拓展及其物理含义,进而以方法为主线,对这一领域具有代表性的研究成果进行了分类和评述,讨论了该课题的研究对地下水流和溶质运移的模拟分析乃至整个多孔介质流体运动研究的意义。     

新疆哈密坡子泉地区首次发现隐爆角砾岩筒

新疆哈密坡子泉地区首次发现的隐爆角砾岩筒处在塔里木板块北缘活动带卡瓦布拉克微板块之上,基底地层为前寒武系,盖层主要为石炭系,受ＮＥ向断裂带控制。隐爆角砾岩特征及产出环境相似于金伯利岩。