The freeze-thaw cycles-time analogy method for forecasting long-term frozen soil strength

To determine the stability of a frozen soil structure, the soil’s long-term shear strength must first be determined. Freeze-thaw cycling is a weathering process in soil (i.e., a process of energy input and output). In cold climates, the freeze-thaw cycle (FTC) has a great influence on long-term strength and stability of soil, which are important considerations for frozen soil engineering. This paper offers a brief introduction to the spherical template indenter and introduces the FTC-time analogy method for forecasting long-term strength of frozen soil. Using the number of cycle repetitions (numbers of freeze-thaw cycles) and the cycle duration (minutes), we calculate the long-term strength of the curve family and their normalized curves, which allows us to predict the long-term frozen soil deformation and strength. Because of the soil transformation that occurs due to the number of repetitions and the duration of FTCs, the results of earlier research can be compared. The FTC-time analogy method can be used to solve problems of forecasting long-term frozen soil strength, as well as for research concerning frozen soil engineering.     

大气影响带对膨胀土边坡稳定的影响及对策

以南水北调中线南阳某段膨胀土渠坡工程为依托,针对大气影响带深度对膨胀土边坡的影响及应对措施,采用GTS-NX岩土有限元数值计算软件建立有限元模型并进行边坡抗滑稳定分析。结果表明,当大气影响急剧层深度大于1.0 m后,边坡安全系数明显下降,当深度到达2.0 m,边坡接近极限平衡状态,水泥改性土换填厚度宜取2.0 m。     

探究建筑工程软土地基处理的关键技术

对国内建筑工程领域软土地基处理技术存在的主要问题进行了全面的总结,深入的剖析了软土地基常用的关键技术与处理方法,以实现软土地基处理工程项目的经济效益与社会效益。     

谈建筑施工企业成本控制

通过列举实际工程中的相关管理经验,分别从标准化工作流程、建立完善的责任成本制度、严格的技术审核和方案优化、健全材料管理制度四个方面详细地阐述了建筑施工企业应如何有效控制成本,以提高施工企业的竞争力。     

A constitutive model for saturated compacted soils under undrained shear condition

Abstract

In this paper, elasto‐plastic constitutive equations extended from theory of plasticity and based on laws of thermo‐dynamics were derived to predict the mechanical behavior of saturated geological media. Besides, these equations can also be adapted to form the stiffness matrix for finite element analysis on deformation and stress distribution in geotechnical engineering practice. The test data were obtained from compacted crushed mudstone under consolidated un‐drained triaxial tests with pore water pressure measurement. The preparation of the specimen was different from those which had usually been adopted. Hence, it is hoped that this study will throw some light on the constitutive equations applied on compacted geological media.     

Fuzzy soft hypergroups

We propose the concept of fuzzy soft hypergroups and explore two particular classes of them, namely fuzzy soft closed hypergroups and fuzzy soft ultraclosed hypergroups. Moreover, we study the image and inverse image of a fuzzy soft (closed, ultraclosed) hypergroup under a fuzzy soft map.     

An analytical solution for geotextile-wrapped soil based on insights from DEM analysis

This paper presents a novel analytical solution for geotextile-wrapped soil based on a comprehensive numerical analysis conducted using the discrete element method (DEM). By examining the soil–geotextile interface friction, principal stress distribution, and stress–strain relations of the constituent soil and geotextile in the DEM analysis, a complete picture of the mechanical characterization of geotextile-wrapped soil under uniaxial compression is first provided. With these new insights, key assumptions are verified and developed for the proposed analytical solution. In the DEM analysis, a near-failure state line that predicts stress ratios relative to the maximums at failure with respect to deviatoric strain is uniquely identified; dilation rates are found to be related to stress ratios via a single linear correlation regardless of the tensile stiffness of the geotextile. From these new findings, the assumptions on the stress-state evolution and the stress–dilatancy relation are developed accordingly, and the wrapped granular soil can therefore be modeled as a Mohr–Coulomb elastoplastic solid with evolving stress ratio and dilation rate. The development of the proposed analytical model also demonstrates an innovative approach to take advantage of multiscale insights for the analytical modeling of complex geomaterials. The analytical model is validated with the DEM simulation results of geotextile-wrapped soil under uniaxial compression, considering a wide range of geotextile tensile stiffnesses. To further examine the predictive capacity of the analytical model, the stress–strain response under triaxial compression conditions is solved analytically, taking both different confining pressures and geotextile tensile stiffnesses into account. Good agreement is obtained between the analytical and DEM solutions, which suggests that the key assumptions developed in the uniaxial compression conditions also remain valid for triaxial compression conditions.     

提高泥水盾构进排浆管软连接使用寿命的研究

对大直径泥水盾构泥水系统在施工方面存在的问题进行了仔细分析,结合软连接爆管漏浆的主要原因,总结了泥水盾构进排浆管软连接使用和改造的技术措施,以提高盾构施工效率。     

机械合金化法制备Finemet非晶粉体的研究

利用高能卧式搅拌球磨机,研究了利用机械合金化法制备Finemet非晶粉体的工艺,研究结果表明,通过高速球磨可以得到部分非晶粉体。非晶化机制是局域熔体的快速冷却,粉体结块和粘壁,是机械合金化法制备高纯度Finemet非晶粉体的主要阻碍因素。     

基于水利施工中软土地基的处理方法研究

地基是水利建筑工程中的基础结构，在整个工程施工中占据着重要的位置。由于地基施工具有隐蔽性的特点，所以给施工提高了一定的难度。基于此，本文就对水利施工中软土地基的主要处理方法进行了分析探讨。