考虑土性和初始含水率影响的真空预压室内试验

基于传统的真空预压室内模型试验,对试验中需加入的不同初始含水率和不同土性两个变量进行了研究,分析了两个试验因素对真空预压加固效果的影响,主要包括加固后土体径向强度和含水率的分布规律,为同类问题的研究提供了依据。     

The influence of soil moisture transfer on building heat loss via the ground

In this paper, the influence of soil moisture transfer on building heat loss via the ground is investigated by comparing fully coupled simulations with linear thermal simulations. The observed influences of coupling are (1) the larger amplitude of surface temperature, (2) the variation of thermal conductivity with moisture content, and (3) the advection of sensible heat by liquid transfer. In a parameter study, it is shown that these conclusions hold for a variety of climates, soils and foundation constructions. However, given the current accuracy level of standard methods, the integration of coupling effects in these calculation methods cannot be defended.     

Equilibrium moisture content of clay bricks: The influence of the porous structure

The comprehension of the influence exerted by the material microstructure on the hygrometric properties of clay bricks plays a fundamental role in order to control the condensation phenomena and to avoid the deterioration of the masonry structure. The equilibrium moisture content (MEq) of ordinary and lightweight clay bricks was measured and the correlation with microstructure and pore morphology was investigated. The influence of the pore size and specific surface on the amount of MEq was found to be prevalent when compared to the other physical variables. A statistical model was also set up in order to predict the MEq values.     

砂土EPS颗粒混合轻质土的最优击实含水率

为了明确击实含水率对砂土EPS颗粒混合轻质土的密度和强度的影响,采用2因素(水泥添加量和EPS颗粒置换率)5水平均匀试验设计确定了5个不同配比,利用密度试验和无侧限抗压强度试验进行了研究。为了确定砂土EPS颗粒混合轻质土的最优击实含水率,引入了基于比强的最优击实含水率确定方法,并采用二分法(初始击实含水率设为6.5%和13%)寻求了每个配比的最优击实含水率,基于物理分析和试验数据给出了最优击实含水率的计算式。研究发现:击实含水率的增加有利于提高击实效果,对水泥的胶结作用则是先提高后降低;基于比强的最优击实含水率确定方法是适宜的;最优击实含水率受到EPS颗粒置换率和水泥添加量的影响。     

Natural dam breaching due to overtopping: effects of initial soil moisture

Natural dams formed by landslides may produce disastrous floods after dam outbursts. How the breaching characteristics of natural dams are affected by initial soil moisture has remained insufficiently understood. In this paper, we present the results of a series of laboratory tests that assessed five different initial soil moistures (0.3, 2.4, 4.2, 7.3, and 10.3%). Under the present experimental conditions with dams composed of gravel–sand–clay mixtures, the failure of natural dams was primarily caused by the erosion of overtopping flow, and lateral mass collapse also caused breach widening. According to the test results, three stages of the breaching process of natural dams made of different initial soil moistures were observed. The results show that peak discharge increased with the increase in the initial soil moisture, while the breaching time and height of the residual dam decreased. In the process of the breach, the backward erosion was weakened gradually with the increase in the initial soil moisture. When the initial soil moisture increased, the breach deepened faster than it widened, and the ratio of the breaching width to depth after dam outburst tended to be greater than 1 at first and then less than 1. A function of the breaching width and depth is established, making it possible to calculate both variables. This function is based on a shape parameter that linearly decreases with initial soil moisture.

     

Dependence of soil aggregation and reaggregation on changes in moisture content

For lacustrine cohesive soils the interdependence of primary sample moisture content and the percentage content of the aggregate fraction has been demonstrated. Analyses have been carried out on samples of the same granulometric and mineral content. It has been proved that in the process of soil drying the content of waterproof aggregates changes. Especially their maxima and minima occur at moisture contents within the range corresponding to the liquidity and shrinkage limits and maximum hygroscopicity. The main thesis, that changes in moisture content have a significant influence on the processes of aggregation, disaggregationaand reagreggation of soils has been proved.     

花岗岩残积土颗粒吸着含水率对液性指数影响

通过对花岗岩残积土的颗粒吸着含水率试验及测试数据的统计与分析，阐述花岗岩残积土的特性，并对土工试验中花岗岩残积土的颗粒吸着含水率的利用提出几点看法。     

爆炸成腔与爆炸衬砌对土体含水率的影响

介绍了土中爆炸成腔与爆炸衬砌的试验步骤,给出了爆炸形成腔体的实测参数。对爆炸成腔与爆炸衬砌周围土体含水率的实测数据进行了分析。研究结果表明,爆炸成腔后在腔体壁面附近的土体中依次形成了含水率降低区、含水率升高区和含水率恢复区。爆炸衬砌后砌体周围土体含水率的分布状态是爆炸成腔和爆炸衬砌作用叠加的结果。爆后砌体周围土体含水率的分布分为水分渗入区、含水率降低区、含水率升高区和含水率恢复区。     

非饱和土抗剪强度与含水率的关系研究

针对非饱和土抗剪强度与含水率的关系进行了试验研究,得出了在相同的密度状态下非饱和土的强度与含水率密切相关,随着含水率的增加,非饱和土的粘聚力和内摩擦角总体均呈现递减的趋势,并且含水率对粘聚力的影响要比对内摩擦角的影响大。     

含水率对压实黄土变形和强度的影响研究

以长临高速路某一区段的压实黄土为材料,进行了不同能量下的击实试验,设计了在不同含水量下压实黄土的固结试验和剪切试验,并获得了相应的规律,通过试验证明含水率是影响压实黄土工程性质的重要因素。     

含水率对粉煤灰混凝土强度增长的影响研究

通过测试不同配合比、不同含水率的混凝土的抗压强度,研究含水率对混凝土强度发展的影响规律。结果显示,混凝土在28d标准养护后,含水率大的混凝土抗压强度增长较含水率小的混凝土要小。     

初调节和运行调节对供暖节能的影响

分析了供热采暖运行中，初调节和运行调节对供热系统节能的影响，并介绍了初调节和运行调节的几种方法。对改善供热效果、提高供热系统热能利用率有积极指导作用。     

含盐量与固化材料掺量对固化盐渍土抗压强度的影响

为解决滨海盐渍土的低强度和大变形问题,采用水泥、石灰、SH固土剂固化盐渍土,研究含盐量、固化材料掺量、养护龄期和浸泡用水对固化土抗压强度的影响.结果证实:含盐量大于1%,固化土抗压强度随含盐量的增加而减小;掺加水泥、石灰、SH固土剂均可提高土的强度和水稳性;随养护龄期的增加,固化土的抗压强度增加;石灰固化土和SH固土剂...     

土壤水分迁移对地埋管换热器夏季性能的影响

基于一维线热源理论,建立了同时考虑温度和含水量变化的土壤热湿传递线热源模型。针对地源热泵夏季运行工况下地埋管周围土壤温湿度的变化进行了数值模拟,结果显示,水分迁移对土壤含水量的影响主要集中在钻孔内。对模拟结果与一维热湿传递实验结果进行了对比,发现二者具有较高的相似性。数据拟合得到不同土壤初始质量含水量下对普通线热源模型地埋管换热量的修正公式。通过对不同埋深地埋管换热量的加权分析,认为当夏季平均地下水位高于-20m时,可以不考虑水分迁移引起的换热量偏差。     

The influence of a large city on some soil properties and metals content

Urban soils differ from the rural ones by the fact that they are more strongly influenced by anthropogenic activities. This influence is often reflected by a high degree of contamination. To investigate the influence a large city can have on its soils and on the surrounding ones, samples within the city of Torino, Italy were compared with a set of surrounding soils developed from the same alluvial parent material. City-country trends were investigated by spatially managing the samples. Results show that the city plays a key role in concentrating some pollutants, such as Pb, Zn, and Cu within its borders. Lead is the element most enriched in the city, presenting a pollution index of 7.5 calculated comparing the two sets of samples. Ni and Cr appear to have a strong natural contribution. The spatial distributions for Pb, Cu and Zn present an abrupt division between urban and rural samples. Unexpectedly, the transport of pollutants from the city to the surrounding areas seems to be limited as no city-country trends with distance are identified. The pH and the sand fraction result also influenced by the city, showing high values. The investigation of possible city-country distance trends has shown to be effective in evaluating the impact a city can have on its soils and on the transport and deposition of contaminants on the surrounding ones.     

施工含水量对土质路基的影响

结合土质路基的特点,就土基施22含水量对路基强度和稳定性的影响进行了分析,并根据工程实践,提出了填土路基施工过程中水稳性控制的技术措施,以期保证路基工程质量。     

Shear strength of swelling soils with variability in normal stress and initial moisture content

Institute of Mechanics and Institute of Geological Sciences, Academy of Science of the Armenian SSR, Erevan. Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 5, pp. 24–25, May, 1988.     

基于湿变量的膨胀土初始裂隙模型及影响因素分析

含水率变化时膨胀土湿胀干缩引起裂隙开展,裂隙的形态特征影响着膨胀土强度、渗透及变形性能。基于弹性力学理论,采用湿变量代替基质吸力来研究膨胀土的应力和变形特性,推导考虑湿变量的膨胀土湿变应力解析解;结合静力平衡条件和饱和土抗剪强度理论,建立基于湿变量的膨胀土初始裂隙模型,获得脱湿条件下膨胀土初始裂隙深度、间距和宽度的定量表达式;通过裂隙开展试验结果与模型计算结果对比分析,验证模型的合理性;最后对裂隙间距和宽度与土体弹性模量、收缩系数、湿变分布系数和凝聚力的关系进行了敏感性分析。     

The influence of heat treatment on the metallic and polycyclic aromatic hydrocarbon content of sewage sludge

Heat treatment followed by vacuum filtration or filter pressing is one method of dewatering sewage sludge. The concentrations of certain heavy metals and polynuclear aromatic hydrocarbons in raw sewage sludge, treated sludge cake and the resultant liquors have been determined in samples collected from three sewage treatment works in the United Kingdom utilising heat treatment. Mass balances have been calculated using the results obtained and the degree of resolubilisation of these materials which occurs during the treatment process has been determined.