软土地基处理方案的技术经济分析

结合井睦高速公路工程项目中的山涧淤泥质土-砂混合软土地基,通过采用松木桩、CFG桩和水泥深层搅拌桩对该软基进行处理,并对这3种软基处理方案进行技术比较与经济分析,以便得到最优处理方案.研究表明:松木桩的造价在3种处理方式中是最高的,而且松木桩受处理深度和承载力的限制,它不是最佳的选择方案;在相同的条件下,CFG桩法处理地基的造价是水泥深层搅拌法处理地基的1.4倍左右,造价较为昂贵;最终确定选用水泥深层搅拌桩法加固该工程的淤泥质土-砂混合软土地基.     

强夯加固淤泥质粉质粘土地基试验研究与投产后的实测数据

用强夯法加固１０￣２０ｍ厚流塑状态淤泥质粉质粘土，大幅度地提高地基承载力是很困难的。著者在马钢原料场堆工程中用一般夯能，大体量地将废钢渣及开山废石夯入土中，插入排水板，置换土层软土层改性，大幅度地提高地基承载力和压缩模量。通过投产后的使用与实测，证实是成功的。     

粘土型金矿池浸法选矿工艺

本发明涉及一种粘土型金矿池浸法选矿工艺。粘土型金矿池浸法选矿工艺，其特征是：它由下列步骤实现：1）．原矿破碎：将粘性土矿石破碎至粒径50mm以下；2）．加辅料拌匀：在破碎后的矿石中加入石灰和利渗材料。并搅拌均匀；3）．装料：将上述加入辅料后的矿石倒入池中，装满池后，矿面应扒平，并铺上一层草料遮盖；     

大型风机基础及平台设计与施工

炼铁厂老风机房2006年新上的一台D1650离心风机，地基为粉质粘土，按地基土压板试验情况及利用计算软件进行沉降及软卧计算，设计采用天然地基与换填地基上的浅基础。由于该工程的试验、设计与施工紧密配合，施工安全可靠，成为炼铁厂联合设计院设计大型风机基础及平台的成功实例。本文介绍其设计思路、施工要点和实施效果。     

泉州丰泽某软弱土场地岩土工程勘察与基坑支护设计探究

随着我国城镇化进程的不断加快,城市人口不断扩张,对建筑空间提出了更高的要求,这给了建筑行业发展提供了机会,同时并非所有地区地质情况都能为建筑建设提供良好条件,软土地区便是如此。软土指的是天然孔隙比大于或等于1.0、天然含水量大于液限、具有高压缩性、低强度低,高灵敏度、低透水性和高流变性,且在较大地震力作用下可能出现震陷的细粒土,主要包含了淤泥、淤泥质土、泥炭、泥炭质土等。由于软土地基的特点,容易导致地基沉降不均匀,抗剪强度较低,对上部结构的稳定性有着非常大的威胁,因此在施工之前,必须做好相应的勘察和基坑支护工作。根据基坑的特点设计科学的支护方案,只有这样才能保证建设过程中的安全,同时保证建设完成后建筑能够稳定运行。本文将结合泉州市丰泽区某软土地基工程建设的实际情况,浅谈如何做好软土地基岩土工程勘察工作以及如何对基坑内支护方案进行设计。     

岩土工程中的淤泥质软土地基处理分析

在岩土工程的设计和施工过程中,采取一定的工艺技术对淤泥质软土地基进行处理是关键性的环节之一,其最终的处理效果直接影响着整个岩土工程的质量。本文从对淤泥质软土的物理力学性质的分析入手,结合具体的工程实际,对岩土工程中淤泥质软土地基的处理方法进行了分析,为今后岩土工程遇到类似的地基处理问题提供参考依据。     

稀土矿物及其混合稀土氧化物

1概述稀土元素（简称稀土）是化学性质极为相似而又十分难于分离的17个元素的总称，它包括元素周期表中的15个镧系元素及同族的副族元素钇和钪。“稀土元素”有人曾认为是一种“稀少”又像“土”的元素，其实并不是这样，在地球上“稀土”并不“稀”也不是“土”，其总储量约占地壳的0.106％，超过人们常见的元素硼、铜、锡、铅、锌、钴、镍等；性质也不象“土”而是典型的金属，都具有银灰色的金属光泽。1.1稀土元素的发现最早发现的稀土元素是记，它是1794年芬兰化学家约翰·多加林（J．Gadolin）在对斯德哥尔摩湾小岛的伊特必村（Yeter…     

冻土工程特性及变电站建构筑物防冻措施分析

通过对冻土的工程特性研究,分析了常温及低温环境下,粘性土不同含水率对应的力学参数。并针对冻土对变电站建构筑物基础的影响,提出了设置砂砾垫层、选择独立式基础或桩基础、减少基础外侧冻切力等三种具体工程措施。该成果可以为冻土地区电力工程建设提供参考。     

清淤工程4种工程量计算方法的分析与应用

结合“水冲法”抽淤的工程监理实践，介绍了清淤工程淤泥工程量4种不同的计算方法，分析其在应用中的优缺点。     

矿山酸性环境下粘土物理力学特性的试验分析

以矿山蓄污土石坝粘土为原料,对其进行了在矿山酸性环境下物理力学特性的试验分析.试验结果表明,粘土在酸性环境下产生了一系列化学和物理变化,导致粘土的物理力学性质明显改变,比重下降,液塑限降低,抗剪强度、压缩模量降低,使粘土的物理力学性质变差,同时发现其可溶盐增加、孔隙比加大;试验结果对进一步研究矿山污水坝在酸性环境下劣化分析以及对矿山蓄污土石坝的设计、加固、评估有重要意义.     

Evaluation of Water Retention Functions and Computer Program “Rosetta” in Predicting Soil Water Characteristics of Seasonally Impounded Shrink–Swell Soils

Soil water retention is a critical factor influencing irrigation decisions and hence agricultural crop yields. However, information on soil water retention characteristics (SWRC) is seldom available for irrigation planning, crop yield modeling, or hydrological simulations, especially for problematic soils, such as seasonally impounded shrink-swell soils. As large scale direct measurement of SWRC is not viable due to a number of reasons, researchers have developed pedotransfer functions (PTFs) to estimate SWRC from easily measured soil properties, such as texture, organic matter content, bulk density, etc. However, PTF applicability in locations other than those of data collection has been rarely reported. One of the most recent PTFs that has shown overall reasonable predictions in evaluation studies is Rosetta, a numerical code for estimating soil hydraulic parameters with hierarchical pedotransfer functions. Relatively, the development of large databases makes it one of the widely used PTFs. If validated for spatial application, it has immense use potential in countries like India, where data on soil hydraulic properties are seldom available, a deficiency that hampers better simulations in processes, like partitioning runoff and infiltration, assessing evapotranspiration, irrigation scheduling, etc. Rosetta is also relatively flexible allowing estimation of hydraulic properties from easily available minimum input of textural fractions. This study was conducted to evaluate (1) an applicability of four widely used soil water retention functions to describe SWRC; and (2) the computer program Rosetta for its validity. Statistical indices, i.e., root mean square error (RMSE), mean absolute error, maximum absolute error, and degree of agreement (d) were computed to evaluate “goodness-of-fit” of the four functions to the measured SWRC data. These indices were also used to compare measured SWRC with estimates of SWRC by Rosetta. For soil samples collected from 41 profiles, 175 SWRC were measured in the laboratory. The van Genuchten function fitted relatively better (RMSE = 0.052?m3?m?3) to SWRC of clay soils, whereas the Brooks–Corey (BC) function was better in expressing SWRC of clay loam and sandy clay loam soils with RMSE = 0.06 and 0.07?m3?m?3, respectively. Campbell and Cass–Hutson (CH) functions were of intermediate value. Worst performing functions were BC (clay soils), Campbell (clay loam), and CH (sandy clay loam) with corresponding RMSE = 0.059, 0.065, and 0.077?m3?m?3. Estimates of two important points on the SWRC curve, i.e., field capacity and permanent wilting point were predicted with relatively better accuracy for clay and sandy clay loam soils by all the four functions. RMSE and d ranged from 0.027?to?0.043?m3?m?3 and from 0.73 to 0.88 for clay soils. Corresponding values for sandy clay loam soils were 0.008?–0.019?m3?m?3, and 0.92–0.98. However, in clay loam soils, only two functions were found suitable. Estimates of SWRC obtained by applying hierarchical rules in Rosetta were reliable (RMSE<0.05?m3?m?3). Magnitude of average RMSE increased progressively in clay loam, clay and sandy clay loam soils (0.028<0.035<0.042?m3?m?3). The study established that SWRC of the “Haveli” soils could be estimated using generic PTF and thus information that is prerequisite in simulating hydrological processes occurring in seasonally impounded soils could be acquired.     

Probabilistic Analysis of Soil-Water Characteristic Curves

Direct measurement of the soil-water characteristic curve (SWCC) is costly and time consuming. A first-order estimate from statistical generalization of experimental data belonging to soils with similar textural and structural properties is useful. A simple approach is to fit the data with a nonlinear function and to construct an appropriate probability model of the curve-fitting parameters. This approach is illustrated using sandy clay loam, loam, loamy sand, clay, and silty clay data in Unsaturated Soil Database. This paper demonstrates that a lognormal random vector is suitable to model the curve-fitting parameters of the SWCC. Other probability models using normal, gamma, Johnson, and other distributions do not provide better fit than the proposed lognormal model. The engineering impact of adopting a probabilistic SWCC is briefly discussed by studying the uncertainty of unsaturated shear strength due to the uncertainty of SWCC.     

Movement and metabolism of S-benzyl O,O-diisopropyl phosphorothiolate (Kitazin P) and O-ethyl S,S-diphenyl phosphorodithiolate (edifenphos) in various types of soils

Movement and Metabolism of 32P and 35S-double labeled Kitazin P (S-benzyl O,O-diisopropyl phosphorothiolate) and 35S-labeled edifenphos (O-ethyl S,S-diphenyl phosphorodithiolate) were examined with three types of soils, sandy loam, alluvial clay loam, and volcanic ash loam. Vertical movement of both the compounds in soil column was different with soil types, and the order of mobility in soil column was as follows: sandy loam greater than alluvial clay loam greater than volcanic ash loam. Persistence of edifenphos in soil was shorter than that of Kitazin P. Main degradation products at the initial stage of metabolism were S,S,S-triphenyl phosphorotrithiolate, O,O-diethyl S-phenyl phosphorothiolate, S-phenyl dihydrogen phosphorothiolate and diphenyl disulfide in edifenphos and O,O-diisopropyl hydorgen phosphorothioate in Kitazin P. Sulfur atom of Kitazin P was found in sulfuric acid at a minor level through dibenzyl disulfide and toluene-alpha-sulfonic acid, and that of edifenphos was converted to sulfuric acid through diphenyl disulfide and benzenesulfonic acid. Kitazin P under flooded condition of alluvial clay loam was slightly more persistent as compared with upland condition. Sterilized condition of Kitazin P did not cause any appreciable degradation throughout the experimental period, but such condition did not necessarily prevent the degradation of edifenphos.     

Probabilistic Unsaturated Flow along the Textural Interface in Three Capillary Barrier Models

The probabilistic flow within capillary barrier models is evaluated by coupling a first-order reliability (probabilistic) model to a variably saturated flow model. The objective is to determine the most significant uncertain variable to probabilistic flow and the effect of different textural combinations. The model inputs include the mean and standard deviation of each uncertain variable. The van Genuchten curve-fitting model for unsaturated flow is used. The uncertain flow variables are saturated water content, residual water content, saturated hydraulic conductivity, and model parameters alpha (α) and n. A clay loam soil sample overlying a loamy sand sample, a clay loam sample overlying a sand sample, and a loamy sand sample overlying a sand sample are used to represent finer soils overlying coarser soil. Evaluations near the textural interface show that model parameters alpha (α) and n=most significant uncertain variables. These are related to the water entry pressure and the width of pore size distribution of the soils. Generally, soils that have the least uniform pore size distribution are the most effective capillary barriers. In this study, the clay loam overlying loamy sand satisfied this condition and performed better than the other soil combinations.     

Sorbent Wicking Device for Sampling Hydrophobic Organic Compounds in Unsaturated Soil Pore Water. I: Design and Hydraulic Characteristics

The hydraulic characteristics of horizontally installed sorbent wick sampling devices were evaluated through wick tracer studies and laboratory soil column experiments to assess the influence of horizontal wick length and sampler interface design on sampling pore water in unsaturated soils. The nominal sampler design consisted of a cylindrical porous metal interface packed with granular-activated carbon encapsulating the end of a fiberglass wick that extended 100 cm horizontally from the interface before dropping 100 cm vertically to a collection vessel. The maximum sampling rate of horizontally installed wick systems declines exponentially with increasing horizontal wick length, while the vertical length influences the range of soil–water pressures that may be sampled. The nominal design sampled pore water from clay loam laboratory columns at 8 to 14 mL?h?1 under steady-state infiltration conditions and 2 to 5 mL?h?1 under draining conditions across a ?10 to ?45 cm H2O soil–water pressure range. Sampling rates in medium-grained sand under similar flow conditions were less than that of the clay loam due to reduced water content and reduced interface/soil contact area. An analysis of observed sampling velocities versus calculated soil water contents and hydraulic conductivities indicated that the design performs best when the soil water content is greater than 0.15 and unsaturated hydraulic conductivity is greater than 0.2 cm?h?1. A hydraulic model was developed that estimates the sampling velocity of the nominal design based on sampler interface pressure, which was linearly correlated with soil pressure.     

盾构在砂层中的施工技术探讨

盾构隧道在砂层施工时,由于砂性土摩擦角较大,渣土流动性差,排土困难,容易发生喷涌,造成地面沉降,影响周边建筑物、管线与道路安全。本文以郑州市轨道交通1号线博学路站～体育中心站区间隧道盾构施工为例,认为砂层施工中必须合理设定土压、改良渣土、严控出土量、防止螺旋输送机喷涌、盾尾密封与注浆工作,才能确保盾构在砂层中的平稳、高效掘进。     

Wastewater Reuse Effects on Soil Hydraulic Conductivity

The wastewater total suspended solids (TSS) concentration effects on the saturated hydraulic conductivity, Ks, of a clay and a loam soil were investigated on laboratory repacked soil cores by a constant head permeameter. Both municipal wastewater (MW) and artificial wastewater (AW) with different TSS concentrations were used, with the aim to evaluate, by comparison, the effects of biological activity. The development of a surface sealed layer was investigated in loam soil columns supplied with AW and equipped with water manometers at different depths to detect the hydraulic head gradient changes. In the loam soil, Ks reduced to about 80% of the initial value after infiltration of 175?mm of MW with TSS = 57–68?mg?L?1. Reductions in Ks were more remarkable in the clay soil. An empirical relationship was proposed to predict the relative hydraulic conductivity, Kr, i.e., the ratio between actual and initial hydraulic conductivity versus the cumulative density loading of TSS. Hydraulic head gradients in the top layer (0–20?mm) of the soil columns increased during application of AW, as a consequence of the formation of a sealed layer, denoting that the surface pore sealing was the main mechanism responsible for the observed Ks reductions. Laboratory data were gathered in a numerical simulation code specifically created to assess the consequences of Ks reduction on water movement through the soil profile. Simulation of both ponded and sprinkler irrigation with MW resulted in reduced infiltration and increased surface ponding condition compared to the application of fresh water (FW).     

新型炮泥的研制

在剖析宝钢高炉原用炮泥的基础上，采取强化骨料、调整结合剂、使用添加剂等措施，研制新型铁口炮泥，经宝钢３号高炉试验使用考核，月平均出铁时间３ｈ／次以上，出铁量接近１２００ｔ／次，出渣率＞８７％。     

Influence of Subsurface Drainage on Soil Temperature in a Cold Climate

Soil temperature during springtime is an important factor for crop establishment and growth in poorly drained soils of northwest Minnesota. In this region, shallow water tables causing spring planting delays and excess water conditions during the growing season, may have contributed to significant unplanted cropland and yield reductions in recent years. Temperature is a regulating factor for many biological and chemical processes in the soil. One of the most commonly cited benefits of subsurface drainage on poorly drained soils is faster soil warm-up in the spring. Previous studies of this phenomenon do not provide definitive conclusions concerning the influence of soil drainage on soil temperature. The results of three site years of field observations of soil temperatures from drainage research plots at two locations in northwest Minnesota are presented herein. Replicated soil temperature and water table depths were measured continuously at five depths for two drain spacings and an undrained treatment. Subsurface drainage was found to significantly increase soil temperatures in both a coarser textured Vallers loam soil and a finer textured Hegne silty clay loam soil. Up to 4°C temperature increases occurred primarily between May and July with the greatest increases at 30–60?cm depths. Treatments with narrow drainage spacing showed a greater spring temperature increase than treatments with wider drainage spacings.     

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The possible contamination of groundwater by the insecticide carbofuran was assessed with the behavior assessment model (BAM) and groundwater pollution-potential model (GWP). Dissipation coefficients of this insecticide in two subtropical soils at different moisture contents and soil temperatures were studied by determining the degradation and adsorption of the herbicide in soils. Movement of carbofuran was studied by leaching the insecticide in a soil column in the laboratory. Under 40% field capacity and at 25 degrees C, more than 80% of carbofuran residue was found in both Luchu clay and Yuanlin silty clay loam after incubation for 63 days. The results indicate that the higher the moisture content in the soil, the less the carbofuran residue under the soil moisture below the field capacity. Carbofuran tends to dissipate more easily in Yuanlin soil than in Luchu soil. The distribution coefficient (Kd) with r2 of 0.69 and 0.92 for Luchu and Yuanlin soils, respectively, was found using the first-order kinetics law. In leaching experiment, carbofuran exhibited easier movement in Luchu than in Yuanlin soil.