橡胶集料混凝土强度与渗透性的关系

对橡胶集料混凝土渗透性与抗压强度进行了试验研究.分析了橡胶集料混凝土的渗透性与抗压强度的关系.试验结果表明在掺有橡胶微粒的情况下,其抗压强度基本上还是随着混凝土的抗压强度的变化而变化,呈现出一定的线性关系.但由于橡胶微粒的掺入,与没有掺入橡胶微粒的混凝土与橡胶集料混凝土相比较,其渗透性与强度的关系表现出一定的突变.     

橡胶混凝土介质渗透性试验研究

试验研究了橡胶微粒掺量对混凝土抗渗、碳化、氯离子渗透以及硫酸盐侵蚀的影响,分析了橡胶微粒降低混凝土抗介质渗透性的厚因,并且采用微观试验进行了机理论证.     

滑坡体低渗透性含水层的虹吸抽水试验方法

由于抽水泵流量远远大于单孔单位涌水量,因而传统抽水试验在低渗透性含水层中"一抽即干",无法形成稳定流。本文利用小直径塑料管代替抽水泵进行了虹吸抽水试验,先进行了3mm和4mm塑料管对比试验,然后采用4mm塑料管,进行二路、四路、六路组合虹吸抽水试验。试验结果表明,多路塑料管的出水能力与低渗透性含水层涌水量匹配,可以形成达西定律要求的稳定流,适用于裘布依稳定流公式,可以计算出该区的渗透系数和影响半径。该试验为低渗透性含水层滑坡区的水文地质勘查提供了一种新的思路和操作手段。     

微生物在不同营养盐环境下矿化产物研究

氯化钙环境下微生物诱导产生碳酸钙沉淀(MICP)过程中,尤其在混凝土结构裂缝修复加固中,多余的氯离子可能会对混凝土结构物中的钢筋产生腐蚀及钝化作用。为了进一步研究微生物在不同营养盐环境下矿化产物的晶体物相及力学性能,通过在尿素中分别添加氯化钙、醋酸钙、醋酸镁形成三种不同营养盐,对完成胶结试验的砂柱采用X射线衍射测试分析其胶结的晶体物相,并通过扫描电镜(SEM)分析其微观结构形貌,对比分析三种营养盐胶结砂样的强度变化。试验结果表明:以醋酸钙、氯化钙为营养盐的胶结砂柱的胶结物主要成分分别为霰石晶簇和方解石晶体;以醋酸镁为营养盐的胶结砂柱的胶结物主要成分为海泡石型硅酸镁、菱镁矿型碳酸镁;霰石晶簇胶结物形貌更为紧密的胶结砂柱表现出的力学性能优于后者。在混凝土结构裂隙修复过程中,以醋酸钙对替代氯化钙作为营养盐在MICP中具有较好的工程意义。     

砂-膨润土混合物膨胀力影响因素的研究

在放射性废料地质处置中，砂－膨润土混合物可用作缓冲回填材料，因而引起了人们对其性能的更加关注。通过室内试验，初步研究了砂－膨润混合物在不同含水量（4％－17．9％）、膨润土含量（10％－50％）和干密度（1．35－1．84g/cm^2）状态下的膨胀性能。通过对试验结果的分析，获得了一些有意义的结论。试验研究表明：砂－膨润土混合物的膨胀性能取决于其干密度、膨润土含量和含水量。含水量小于塑限含水量时，其膨胀稳定后的影响因素的分析中，使用蒙脱石的填充率这一参数来描述膨胀力。把粘土矿物含量、干密度的影响都统一到蒙脱石填充率对膨胀力的影响，建立了蒙脱石密度与膨胀力的函数关系。     

Al_2O_3对灰砂系统水热反应的影响

(一)引言自然砂中常常含有粘土矿物或Al_2O_3,这些矿物必将对灰砂反应的进程、水化物的生成与转化及制品的性能产生影响。国内外的一些     

粘土矿物与斜坡失稳

作为微米级材料，粘土矿物的单晶尺寸及特殊晶体结构使其集合体-粘土呈现低渗透性、分散-凝絮性及粘滞性等重要工程特性。除沉积岩斜坡含粘土矿物外，76％以上的斜坡岩石造岩矿物还可形成次生粘土矿物。粘土矿物广泛分布于原生沉积岩、三大岩类风化带及第四系松散堆积物构成的斜坡中。泥屑岩因含粘土矿物而易于失稳，且水稳定性差。次生粘土矿物的形成将引起源矿物、矿物集合体及岩块的强度与变形特性的显著变化，诱发岩石向松散介质转化。宏观结构面是粘土矿物最主要的形成和聚集场所，结构面及其内侧一定范围内不同成因粘土矿物的淀积将导致结构面及岩体强度的衰减。粘土矿物是滑坡滑带的常见矿物组分；粘土滑带可以在滑体与滑床之间起到润滑作用。滑带中粘土矿物的含量越多，其润滑效应越显著。粘土型滑带还具有隔水边界之功效，可将滑体与周围介质隔离，使之成为独立水文地质单元，提高坡体拦截、吸收渗入水的能力及斜坡稳定对降雨过程的敏感度。粘土矿物可以促进斜坡时效变形，甚至成为斜坡破坏的关键因素，对斜坡演化及失稳的贡献是显著的。     

沉积和构造特征对含水层富水性的影响

为了从含水层本质特征定量评价含水层富水性及其影响指标的相关性,根据研究区含水层沉积和构造特征,并结合地质及水文地质补充勘探资料,确定了影响含水层富水性的指标包括含水层砂地比、含水层厚度、粗砂岩厚度、粗砂岩层数、断层分维值和褶皱分维值,采用灰色关联度对6项影响指标与含水层富水性的相关性进行了研究。通过计算分析,对含水层富水性影响由大到小依次为断层分维值、含水层厚度、含水层砂地比、砂岩层数、粗砂岩厚度和褶皱分维值。说明了含水层富水性受到构造的影响较大,但是沉积特征同样对含水层富水性起到了重要的影响作用。在对含水层富水性进行分析的过程中,考虑到构造控水的同时,含水层沉积控水作用同样应该受到重视。     

盐度对口虾蛄存活和生长的影响

在不同盐度下,对体重13³5 g的口虾蛄O ratosquilla oratoria进行存活和生长试验。存活试验包括盐度突变试验和渐变试验,生长试验的盐度梯度设为24、28、32、36,每组放口虾蛄6只。结果表明,盐度对口虾蛄的存活及生长有较大影响,口虾蛄存活的盐度为2035 g的口虾蛄O ratosquilla oratoria进行存活和生长试验。存活试验包括盐度突变试验和渐变试验,生长试验的盐度梯度设为24、28、32、36,每组放口虾蛄6只。结果表明,盐度对口虾蛄的存活及生长有较大影响,口虾蛄存活的盐度为20⁴0,适应盐度为2440,适应盐度为24³6,生长的最适盐度为32左右。     

粉煤灰掺量对机制砂混凝土性能的影响研究

研究了不同种类砂对混凝土强度和拌合物和易性的影响,并探究了粉煤灰掺量对全机制砂混凝土强度和抗氯离子渗透性能的影响。结果表明:机制砂混凝土的强度高于混合砂混凝土和河砂混凝土,但机制砂混凝土和易性较差。机制砂混凝土强度随着粉煤灰掺量的增加而降低,随着养护龄期的增长,后期强度降低幅度变缓;粉煤灰的掺入能够显著改善机制砂混凝土的抗氯离子渗透性;粉煤灰掺量低于30%时,机制砂混凝土强度和耐久性等各项性能良好。     

细粒迁移及组构变化对黏土渗透性影响的试验研究

为进一步探究水化学环境下土体渗透性的变化规律及作用机理,对饱和重塑压实黏土样在不同水化学条件及渗流路径下进行了一系列变水头渗透试验,分析了不同浓度的NaCl溶液在不同渗流路径下对饱和黏土渗透性的影响。结果表明：不同干密度试样的渗透性随浓度增加展现出较大的差异,干密度为1.40 g/cm³时,渗透系数呈先升后降,而干密度为1.50 g/cm³时,渗透系数不断降低;逆转渗流方向,试样渗透系数发生突变;孔隙盐溶液浓度周期性变化,试样渗透性不可逆。基于核磁共振（NMR）分析技术,测试了土体内部孔隙结构分布随孔隙盐溶液浓度的变化。最后基于上述试验结果从细粒迁移产生的孔隙堵塞效应和组构改变引起的孔隙封闭效应两个方面,解释了孔隙盐溶液浓度变化对黏土渗透性的影响。     

Numerical Assessment for the Behavior of the Pleistocene Marine Foundations due to Construction of the 1st Phase Island of Kansai International Airport

A series of elasto-viscoplastic finite element analyses is performed to assess the stress and deformation of the Pleistocene marine foundation due to construction of the 1st phase island of Kansai International Airport in Osaka Bay. Attention is paid to the modeling of permeability for Pleistocene sand gravel layers considering the sedimentation environment because the performance of excess pore water pressure is strongly dependent on the extent of distribution as well as the change of thickness of those permeable sand gravel layers. The concept of “mass permeability” is introduced to model the actual process of dissipation of excess pore water pressure in the field. The mechanism for the propagation of excess pore water pressure is also discussed. Special attention is given to the modeling of the compressibility of the highly structured Pleistocene clay layers, exhibiting already significant visco-plastic deformations even in the quasi-overconsolidated effective stress range. The present numerical analyses are found to describe the large and long-term settlement together with the slow dissipation of excess pore water pressure in the Pleistocene clay and sand gravel layers that actually has taken place in the field. A detailed comparison of the distribution of excess pore water pressure and the differential compression for the individual Pleistocene clay layers shows that the calculated performance can well describe the actual behavior of the Pleistocene deposits due to the construction of the 1st phase island of Kansai International Airport.     

鄂尔多斯盆地姬嫄地区长6段超低渗储层敏感性评价

以鄂尔多斯盆地姬嫄地区长6段油层组超低渗储层作为研究对象,在储层岩石学、孔隙结构、储层物性特征等基础上,结合储层"五敏"实验详实数据,解释该地区超低渗储层敏感性及敏感机制。姬嫄地区长6段超低渗储层所展现的敏感性为弱速敏、中等偏弱水敏、中等偏弱盐敏、无酸敏到弱酸敏、弱碱敏、强压敏;且速敏中的临界流速、盐敏中的临界矿化度、酸敏中的临界p H值分别为1.0mL/min、10000mg/L、8.5。储层敏感程度主要受矿物成分和孔隙结构的影响,储层速敏的形成源于其孔隙填隙物-高岭石的存在;绿/蒙混层及伊/蒙混层矿物是引起水敏及盐敏的主要因素;铁白云石及含铁绿泥石等酸敏矿物的存在使部分岩样显弱酸敏;非常杂乱的孔喉结构、受到压力特别容易变形的片状喉道以及岩样中所含的云母、黏土等一些塑性矿物导致储层具强压敏性。储层敏感性评价的意义在于防止储层伤害、保护好储层,可以有效地发挥储层的产能,已达到科学的开采油田的目的。     

Reactivity of aluminium potline waste components with lateritized clay and geotechnical significance for a landfill at Wallaroo,New South Wales,Australia

The Aluminium Industry in the U.S.A. and Australia is making considerable efforts to develop treatment systems for certain solid wastes generated during the refining of aluminium. To date, there are few satisfactory long term alternatives to a secure landfill for disposal of these materials. Studies at Wallaroo in Australia have found anin situ Tertiary weathering profile in Permian rocks that has some useful characteristics for landfill disposal. Since Oligocene-Miocene times, the rocks have been strongly and deeply weathered to clay that has a low permeability. The clays are mainly kaolinite and iron minerals with lesser amounts of gibbsite, minor chlorite, interstratified mineral and montmorillonite. The minerals are in chemical equilibrium with the groundwaters found in the weathering profile. The effects of leachable fluoride and sodium and the high pH on the acidic clay have been studied in batch tests. Distribution coefficients and maximum adsorption capacities from batch and core tests have been measured. High concentrations of sodium and fluoride (important leachate component) have also been passed through a compacted clay core to study effects on permeability. Decreases in permeability and true flow velocity of the NaF water compared with deionized water have been observed. The results are related to internal swelling, dispersion and consolidation characteristics. The effects of the chemical processes on likely long-term permeability of clay liners and clay weathering products have been assessed. Leachate from potlining waste has been reacted with the clay and found to form a new mineral phase that is expected to further reduce permeability. No adverse effects have been observed.     

流固耦合的多元结构深厚覆盖层透水地基的力学特性

深厚覆盖层多元结构坝基在渗流过程中各土层力学差异明显,分析时关注的具体问题也不尽相同,需要深入研究。基于比奥固结理论,考虑土体的非线性流变以及土体固结变形过程中孔隙度、渗透系数、弹性模量及泊松比的变化;借助ADINA流固耦合模块来模拟西藏达嘎水电站坝基渗流场与应力场耦合过程,分析各层力学特性及相互作用。研究表明,透水性较强的表层土体是渗流主要通道,也是渗流进出区和沉降变形体现区,应在上游采取措施提高其压缩模量,下游区域增设反滤层和排水设施;坝基中的粉细砂层是坝基沉降的主要原因,对坝基沉降起主导作用,同时应注意其液化特性对坝基的不利影响;坝基中的承压含水土层对下游上部结构产生向上顶托力,若位置较深,则破坏性较小;坝基深部土层对整个坝基的渗流破坏影响较小,但对沉降和渗流量的影响不可忽视;表层砂卵砾石层和粉细砂层的渗透系数相差较小时,土层间不会发生接触冲刷。此外,还发现坝基孔隙水压力在快速衰减阶段被消散,期间土体固结较快。垂直防渗墙能有效降低渗透坡降和渗流量,将坝基沉降变形控制在防渗墙上游区域,但上游坝基变形对防渗墙产生较大的水平推力,应加大防渗墙尺寸或者采用辅助渗控措施。     

多孔介质中氚的滞留及对相关试验的影响

在进行氚在黏土矿物中的滞留试验基础上,对试验结果进行了总结,分析了滞留现象对相关水文地质、环境地质参数试验的影响。结果表明:氚在蒙脱石、高岭石、伊利石等孔隙介质中的平均分配系数分别为0.15 ml/g、0.10 ml/g、0.12ml/g;氚的绝对吸附量随氚水比活度的增加而增大,绝对吸附量的对数与相应氚水比活度的对数呈直线相关关系;氚的滞留将使野外弥散试验获得的弥散度和弥散系数减小,使得室内示踪试验获得的孔隙水流速比实际孔隙水流速减小5%~25%,使得按照3H测龄方法获得的亚砂土等含水层中地下水年龄增大5%~20%,按照3H-3He测龄方法获得的地下水年龄比实际情况增大4%~18%。     

NUMERICAL SIMULATION OF SALINE UPCONING IN THE PLEISTOCENE AQUIFER OF JERICHO AREA

The existence of fresh groundwater overlaying saline water in groundwater systems is widespread in many inland aquifers and most coastal aquifers. The Jericho district suffers from the phenomenon of saline upconing. The Pleistocene aquifer, which is the main source of water supply for irrigation in the Jericho district, comprises a layer of salt water covered with lenses of fresh water. It appears that drought and heavy exploitation from Jericho wells are the main reasons for the saline upconing problem in the Pleistocene aquifer. The objectives of this research were to (a) investigate the saline upconing phenomena and (b) provide recommendations for control of the fresh and salt-water mixing in the Jericho aquifer underneath a skimming well. A model, which coupled density-dependent flow and solute transport, was used to simulate movement of the salt water under different hydrogeological and operational conditions. Results from the simulations showed that location of the screen has a strong impact on salt-water movement in the well. Reasonable control of saline upconing was observed when the screen was placed against the gravel layers.     

Numerical simulation of ground water protection works for an industrial waste dump

 The use of a deserted clay quarry to collect iron manufacturing-derived special wastes has been carefully assessed with a view to protecting ground water resources. The shallower ground water is of low quantity and poor quality. It is encompassed by a calcarenite aquifer, the bottom of which consists of clays. A limited calcarenite layer is found below, transgressively lying over the main Apulian carbonate shelf. The aquifer carbonate rocks enclose large ground water resources which ultimately flows into the Ionian Sea. A plastic waterproof diaphragm inert to percolation products has been installed to protect ground water against pollution hazards resulting from the disposal of industrial wastes. The dump is actually located in the vicinity of major industrial plants, the basements of which corresponds to the shallow aquifer. Both the basements and the railway cuttings greatly affect the ground water flow. Hydrogeological applied numerical calculation techniques have been used to evaluate the impact of a drainage trench on the ground water flow together with any noticeable influence of the latter on construction works and industrial plants in place. Received: 22 September 1998 · Accepted: 1 December 1998     

砂性地层注浆浆液扩散特性

对南京地区河砂采用筛孔分别为5,2,0.5,0.2 mm 的筛网筛分后,分为不同粒径的砂土,以渗透系数为控制指标,根据试验需要对所用河砂进行配比,模拟出4种砂砾土层。通过对自行研制的一种渗透注浆装置进行室内模拟注浆试验,研究了4种不同颗粒级配的砂样在不同注浆量、水灰比、注浆压力等影响因素下浆液的扩散特性,并在此基础上进行多元线性回归分析。结果表明:浆液扩散半径主要影响因素的主次顺序为注浆压力、渗透系数、水灰比; 注浆量主要影响因素的顺序为注浆压力、渗透系数、水灰比; 结核体强度主要影响因素的顺序为水灰比、渗透系数、注浆压力; 结合试验结果拟合得到了浆液扩散半径、注浆量、结核体强度与渗透系数、浆液水灰比、注浆压力之间的定量关系式; 砂性地层中的浆液扩散半径存在有效半径,为初始半径的75%～80%; 对于在砂性地层中的浆液扩散行为,具有多种浆液扩散模式并存的可能; 所得结论可供类似工程借鉴与参考。