粘土矿物与分散性粘土

松辽盆地和三江平原都存在着会给水利工程带来很大危害的分散性粘土。本文简要介绍粘土矿物与分散性粘土的性质和分微机理。     

分散性粘土筑坝质量控制

南引水库除险加固工程一项重要的施工内容为分散性粘土处理。处理的方法采用分散性粘土掺加一定比例白灰,将分散性粘土变成非分散性粘土,保证土坝力学性能稳定,满足水库蓄水要求。阐述了分散性粘土筑坝质量控制要点。     

分散性粘土堤坝处理措施

分析了分散性粘土堤坝溶洞成因,提出了复合土工膜和白灰土处理分散性粘土堤坝的措施。     

对南部引嫩工程分散性粘土坝的分析

黑龙江省南部引嫩水库33个土坝中除1#、8#、32#坝外,均用分散性粘土修筑,1982年及2000年经过两次处理,目前仍有个别坝段出现严重破坏现象.通过对分散性粘土的物理、力学性质及分散机理等的分析,为今后进一步研究和治理分散性粘土提供依据.     

水质对分散性粘土冲蚀破坏的影响

黑龙江省西部松嫩平原为大面积高钠盐渍土区。区域内的土质大都为分散性粘土。通过现场诃查和取样分析得到了雨水是使这一地区土体冲蚀破坏的主要原因。     

分散性土的鉴别及改性试验

大屯水库、岭落水库、官路水库为比较典型的分散性土,为保证堤坝安全,需要鉴定其分散性等级并进行改性加固。采用双密度计、针孔试验、碎块试验对几个工程的分散性图进行鉴别,确定了分散性等级。取该分散性土试样进行不同剂量的石灰改性试验,进行了改性后反滤试验,确定当石灰剂量达到1.5％时,改善效果最佳。改性土的反滤试验证明,改性土能满足工程需要,为类似工程提供理论借鉴和技术支持。     

冻融循环对季冻土分散性影响及明矾改性试验研究

为测定季冻土的基本物化性质、矿物成分含量,进行分散性随着冻融次数的增加而发生变化的试验,并探究不同明矾用量对季冻土分散性的改性作用,确定对季冻土分散性具有明确改善的用量,探索明矾改性土的分散性随冻融循环次数增加而发生的变化.试验结果表明:本次研究区的季冻土样属于粉质黏土,Na+含量相对较高,并且具有较强的分散性;季冻土样的分散性随着冻融循环次数的增加而增加,并且在冻融循环次数达到7次后,季冻土土样的分散性达到了非常高的水平;含2.5％明矾的改性土样分散性指标也随着冻融循环次数的增加而增加,但在试验设定的20次冻融循环下,依然属于非分散性土.研究成果可为季冻土质路堤稳定性分析及工程改善提供参考.     

包头地区粉煤灰-粘土烧结砖的试验研究

在简要讨论粉煤灰－粘土烧结砖意义和推广应用前景的基础上,重点通过试验研究了粉煤灰－粘土烧结砖的配方,烧结温度,结时间,力学性能,耐久性能,耐久性能和其它性能指标,最后给出了粉煤灰－粘土结砖的优点和可行性。     

昆明地区红粘土工程性质指标的变差特征

本文根据昆明地区11个工程场地红粘土的土工试验资料,讨论红粘土的物理性质指标和力学性质指标的变差特征,根据物理性质指标间的线性关系建立相关方程。     

红粘土的强度机理

从红粘土的水敏性、密实程度与胶结作用这三方面对其抗剪强度的影响进行了试验,研究发现:随着干密度的增大,红粘土的抗剪强度与粘聚力也有了较大的提高,而内摩擦角在干密度较大情况下随含水率变化较为明显。为了探究胶结作用对红粘土抗剪强度的影响,用丙三醇溶液替代水溶液配制土样进行试验,发现胶结物质减少的红粘土试样,其抗剪强度也有了明显的降低,进一步从胶结作用对红粘土的影响方面分析了红粘土的强度变化规律。     

益阳地区红粘土边坡的失稳机理探讨

以益阳地区红粘土为研究对象,对其主要成分进行分析的基础上,探讨了红粘土对边坡稳定性影响的发生机理、失稳特征．同时结合具体例子对红粘土边坡的稳定性进行了计算研究,提出了治理红粘土边坡的基本思路,可为类似工程的红粘土边坡设计与施工提供参考．     

Calculation of the debris flow concentration based on clay content

The debris flow clay content has very tremendous influence on itsconcentration (γ_c). It is reported that the concentration can be calculated by applying the relative polynomial based on the clay content. Here one polynomial model and onelogarithm model to calculate the concentration based on the clay content for both theordinary debris flow and viscous debris flow are obtained. The result derives from thestatistics and analysis of the relationship between the debris flow concentrations and clay content in 45 debris flow sites located in the southwest of China. The models can beapplied for the concentration calculation to those debris flows that are impossible toobserve. The models are available to calculate the debris flow concentration, theprinciples of which are in the clay content affecting on the debris flow formation,movement and suspending particle diameter. The mechanism of the relationship of theclay content and concentration is clear and reliable. The debris flow is usually ofmicro-viscous when the clay content is low (<3%), by analyzing the developing tendencyon the basics of the relationship between the clay content and debris flow concentration.Indeed, the less the clay content, the less the concentration for most debris flows. Thedebris flow tends to become the water rock flow or the hyperconcentrated flow with theclay content decrease. Through statistics it is apt to transform the soil into the viscousdebris flow when the clay content of ranges is in 3%-18%. Its concentration increaseswith the increasing of the clay content when the clay content is between 5% and 10%. Butthe value decreases with the increasing of the clay content when the clay content isbetween 10% and 18%. It is apt to transform the soil into the mudflow, when the claycontent exceeds 18%. The concentration of the mudflow usually decreases with theincrease of the clay content, and this developing tendency reverses to that of themicro-viscous debris flow. There is maximum mean concentration for the debris flowwhen the clay content ranges are between 7% and 11 %. Especially, for the viscousdebris flow, the logarithm formula here is suitable to the concentration calculation with theclay content between 3% and 18%. The maximum concentration calculated by thisformula reaches 2.32 t/m~3, which matches that tested in practice.     

层柱粘土纳米复合材料制备及应用进展

层柱粘土矿物质是一种新型的纳米复合材料．介绍了这种纳米复合材料的制备方法、结构与性能特征及潜在应用前景．     

Viscous property of dried clay

One dimensional and triaxial compression tests of air-dried and oven-dried Fujinomori clay and Pisa clay were carried out. Water content is less than 4.5% and 1.0% for air-dried and oven-dried clay specimens, respectively. In all tests, axial strain rate was changed stepwise many times and drained creep tests were performed several times during monotonic loading at a constant strain rate. Global unloading （and also reloading in some tests） was applied during which creep loading tests were performed several times. Cyclic loading with small stress amplitude and several cycles was also performed to calculate the modulus of elasticity of the clay in tests. Local displacement transducer was used in triaxial compression test to increase measuring accuracy of axial strain. The results show that air-dried and oven-dried clay have noticeable viscous properties; during global unloading, creep deformation changes from positive to negative, i.e. there exist neutral points （zero creep deformation or no creep deformation point） in global unloading part of strain-stress curve; viscous property of Fujinomori clay decreases when water content decreases, i.e. viscous property of air-dried Fujinomori clay is more significant than that of oven-dried Fujinomori clay.     

聚羧酸减水剂在水泥和泥土表面的吸附行为

采用有机碳测定仪研究了水泥、泥土和水体系中聚羧酸减水剂吸附量与吸附时间、减水剂浓度、体系温度的关系。同时,对减水剂吸附模型和吸附热进行了分析,探讨了聚羧酸减水剂在水泥、泥土颗粒表面的吸附特性。结果表明:水泥和泥土对聚羧酸减水剂的吸附量随时间延长不断增加,最后达到平衡,同时,泥土比水泥对减水剂的吸附量要大,泥土的掺入量为0.5%就会大大降低水泥净浆的流动度;聚羧酸减水剂的吸附基本符合Langmuir等温吸附模型,水泥和泥土对减水剂的饱和吸附量分别为3.7mg/g和10.1mg/g;水泥和泥土对聚羧酸减水剂的吸附量随温度的增大而减小,其吸附是一个放热过程。     

武汉原状粉质黏土与其重塑土的试验对比研究（I）：试验结果描述

以武汉沙湖粉质黏土为研究对象,首先借助于高压固结仪,对重塑土和原状土进行了室内侧限的固结试验;其次利用改进的应力控制式常规三轴仪,在不同的加荷路径和排水条件下,对重塑土和原状土分别进行了常规三轴试验研究,并对试验资料进行了较为系统的分析．结果表明：1）原状土的侧压力系数约为0．56,超固结比约等于1．2,为弱超固结土体,其结构屈服压力稍大于其前期固结压力;2）原状土初始的切线模量及其抗剪强度均高于重塑土相应的值;3）在固结排水条件下的三轴剪切试验,原状土的剪胀量要小于重塑土的剪胀量,但在固结不排水条件下,原状土体的剪胀趋势却明显要高于重塑土的剪胀趋势．     

传统PAC混凝除藻方法的改进

采用粘土矿复合聚合氯化铝(PAC)对传统PAC混凝除藻方法进行了改进研究,结果表明,与单加PAC相比,粘土矿的加入可显著增加絮体的密实度,使得沉淀后的活藻絮体在微扰动下不再漂浮上升,且能大大减少沉淀后底泥的体积,还可降低剩余浊度及出水中藻和铝的浓度。     

不饱和聚酯/粘土纳米复合材料的制备与性能研究

通过XRD研究了不饱和聚酯／粘土纳米复合材料的微观结构。结果表明：有机粘土的晶层间距膨胀，用有机粘土制备的不饱和聚酯／粘土纳米复合材料的XRD曲线中反映粘土晶体结构的布拉格衍射峰已经消失，粘土在复合材料中已达到纳米级分散；宏观性能测试结果表明，在有机化粘土添加量适当的情况下，不饱和聚酯／粘土纳米复合材料可实现增韧增强；同时其耐热性能也得到明显改善。     

不同粘土矿物对干酪根生烃的催化作用

分析了典型的粘土矿物蒙脱石、高岭石、伊利石对干酪根生烃过程的影响,认为三种粘土矿物都对干酪根生烃有一定的催化作用,其中以蒙脱石最为显著;阐述了粘土矿物的催化剂机理,并从矿物的结构特征方面分析了不同粘土矿物对干酪根生烃的催化能力,为有机质生烃过程的催化作用提供了理论基础.