盐分对黏性土的沉积特性与表面电位影响研究

为了明晰黏土矿物和盐分浓度在沉积过程中所起的作用及物理机制,选取高岭土、膨润土及两者组成的混合土进行粒径分析试验、沉积试验和Zeta电位测试。结果显示,盐分环境下高岭土和膨润土的平均粒径增大,部分黏粒组向粉粒组转化。高岭土在蒸馏水环境下和盐水环境下,最终都形成土-水的稳定分界面,但是絮凝稳定时间在盐分环境下更短。膨润土在蒸馏水环境下处于稳定的分散体系中,在盐水环境下迅速絮凝沉积。混合土在蒸馏水环境下,上部澄清层和下部沉淀层之间存在土颗粒的悬浮层,且该层的高度最终稳定;盐水环境下,混合土则迅速的发生土水分离。随着NaCl浓度增加,膨润土和高岭土的Zeta电位绝对值降低,因此胶粒组的絮凝行为对平均粒径产生影响,进而影响其沉积特性。     

某废弃煤矿有机污染场地地下水修复治理中试研究

某废弃煤矿竖井经倾倒有机废液,导致环境污染事件,造成巷道及采空区内地下水污染。本文结合场地实际情况,选取倾倒竖井(事故井)及周边区域为中试区域,采用“抽出处理+原位氧化循环”两阶段联合修复技术对污染场地开展中试研究。本文介绍了场地污染概况、地下水修复中试方案设计和实施,以及对修复效果进行评价。结果表明,中试处理后地下水中COD和二氯甲烷最高去除率分别为97.88%和99.74%。中试试验表明, “抽出处理+原位氧化循环”两阶段修复技术,对处理矿区内巷道及采空区等复杂地层结构下深层地下水中有机污染物具有较好的去除效果,可以结合现场实际情形对整个污染场区进行规模应用。     

LOQUAT: an open-source GPU-accelerated SPH solver for geotechnical modeling

Acta Geotechnica - Smoothed particle hydrodynamics (SPH) is a meshless method gaining popularity recently in geotechnical modeling. It is suitable to solve problems involving large deformation,...     

Single subduction zone for the generation of Devonian ophiolites and high‐P metamorphic belts of the Variscan Orogen (NW Iberia)

Within the Variscan Orogen, Early Devonian and Late Devonian high‐P belts separated by mid‐Devonian ophiolites can be interpreted as having formed in a single subduction zone. Early Devonian convergence nucleated a Laurussia‐dipping subduction zone from an inherited lithospheric neck (peri‐Gondwanan Cambrian back‐arc). Slab‐retreat induced upper plate extension, mantle incursion and lower plate thermal softening, favouring slab‐detachment within the lower plate and diapiric exhumation of deep‐seated rocks through the overlying mantle up to relaminate the upper plate. Upper plate extension produced mid‐Devonian suprasubduction ocean floor spreading (Devonian ophiolites), while further convergence resulted in plate coupling and intraoceanic ophiolite imbrication. Accretion of the remaining Cambrian ocean heralded Late Devonian subduction of inner sections of Gondwana across the same subduction zone and the underthrusting of mainland Gondwana (culmination of NW Iberian allochthonous pile). Oblique convergence favoured lateral plate sliding, and explained the different lateral positions along Gondwana of terranes separated by Palaeozoic ophiolites.     

Numerical evaluation of soft inter‐slab joint in concrete‐faced rockfill dam with dual mortar finite element method

Recently constructed concrete‐faced rockfill dams (CFRDs) often use soft inter‐slab joints to prevent axial compression‐induced extrusion damage in the concrete face. Due to the complexity of the multibody contact and the lack of information on the actual behavior of soft joints, it is highly challenging to numerically assess the effect of soft joints in CFRDs. In this paper, we present a numerical approach for the three‐dimensional modeling of CFRDs with hard and soft joints. A dual mortar finite element method with Lagrange multiplier is developed to treat the multibody contact in hard joints with impenetrability condition. The soft joint slab‐filler‐slab contact system is modeled using an equivalent contact interface approach, where the soft contact constraints are imposed using a perturbed Lagrange formulation. Through a series of laboratory tests, the mechanical behavior of soft joint is investigated. An extrusion model for the soft joint is presented and implemented in the dual mortar finite element method. The proposed numerical method is applied to the three‐dimensional analysis of Tianshengqiao‐1 CFRD. Despite the complex multibody contact and strong material and geometry nonlinearities in the CFRD, the proposed method is stable and capable of capturing salient characteristics of the CFRD. Numerical results show that in Tianshengqiao‐1, the employment of soft joints can effectively reduce the axial compression stress, thus greatly alleviating the risk of extrusion damage in the concrete face.     

Modelling the time‐dependent behaviour of granular material with hypoplasticity

This paper presents a constitutive model for time‐dependent behaviour of granular material. The model consists of 2 parts representing the inviscid and viscous behaviour of granular materials. The inviscid part is a rate‐independent hypoplastic constitutive model. The viscous part is represented by a rheological model, which contains a high‐order term denoting the strain acceleration. The proposed model is validated by simulating some element tests on granular soils. Our model is able to model not only the non‐isotach behaviour but also the 3 creep stages, namely, primary, secondary, and tertiary creep, in a unified way.     

ArcGIS Model Builder在历史数据处理中的应用

在智慧潍坊时空大数据与云平台的建设中,需要将历史地形图数据进行数据入库。与传统的地形图人工内业数据入库处理方法相比,基于ArcGISModelBuilder技术对数据处理过程建模,对数据进行自动化处理的做法在作业中具有极大的优势。利用该工具创建了房屋、高程点、控制点等几种地物的自动化处理模型,实现了多种地形图要素的自动化处理,简化了传统的地形图入库作业流程,提高了数据处理效率。该文以潍坊市历史地形图为例,验证了该方法在保证数据质量的同时,能够有效提高数据的生产效率,为历史地形图数据的生产入库提供了切实可行的操作思路和实现工具,同时可为其他地区历史地形图数据入库工作提供参考。     

风电场设计私有云GIS平台架构研究

云计算是目前信息产业最热门的技术之一,GIS厂商纷纷将GIS软件迁移至云计算环境。与国外云计算部署不同,国内更青睐私有云技术,企业、政府机构纷纷搭建私有云GIS平台。针对风电场设计的特点,本文基于目前云计算应用和研究,构建了私有云GIS平台的体系框架,并对平台所涉及的主要关键技术进行了深入探索,对私有云GIS模式下的资源进行了详细的分类,包括核心服务、服务管理、用户访问接口3个部分。其中,核心服务将硬件基础设施、软件运行环境、应用程序抽象成服务,可满足多样化的风电场设计应用需要。     

距离与角度控制的矢量面数据接边检查方法

针对现有接边方法依赖于直线型接边线,难以有效的支持非直线型接边线的数据接边质量检验的问题,提出了一种新的基于距离与角度控制的矢量面数据接边检查方法。该方法利用矢量面到接边线的距离值与弧段转角角度值作为参考量检测接边特征点,通过匹配接边特征点的方式检测接边错误位置,不依赖于接边线的具体形态,能够适用于任意类型接边线的矢量面数据接边检查。以第一次全国地理国情普查数据接边检验为实例进行验证,结果表明,该方法的漏检率为0%,准确率达到95%以上,有效地提升了接边线非直线的矢量面数据接边质量检验的准确性及效率。