反倾岩质滑坡破坏模式及发育机理研究

反倾岩质滑坡因结构面特点,往往易发生变形破坏,危害较大。以怒江流域的格堆村滑坡为例,在地质调查的基础上,采用离散元数值模拟技术,对滑坡变形累积到破坏的全过程进行了模拟,结果表明:斜坡体的位移最先出现在坡表,随后向坡内扩展,且位移量呈现出由坡外向坡内逐渐减小的趋势,表现出倾倒破坏的特征;综合野外调查及数值模拟结果推断,格堆村滑坡的发生是内外因素共同作用的结果,河谷下切为坡体变形破坏提供了临空面,卸荷作用使坡体岩性变差,最终导致变形破坏,且破坏模式为倾倒-弯曲-滑移。     

某管道滑坡作用下的变形及潜在危险分析

某天然气管道xx段发生泄漏燃烧事故,现场勘察显示管道穿越段存在滑坡活动迹象,目前已采取工程措施进行治理,但对滑坡的发育特征、滑坡对管道的作用方式及后期潜在危险认识还不充分,为了管道及周围居民的安全有必要进行深入分析。通过前期勘察工作掌握了滑坡的基本特征、建立了地表位移监测网,并进行了持续7个月的地表位移监测,对滑坡的发展趋势有了较为明确的认识;同时采用无人机摄影测量技术对滑坡进行了三维重建,从宏观上全面解析了滑坡的裂缝发育特征。研究表明:管道泄漏点位于滑坡边缘软硬岩交接处,滑坡的变形主控因素为后缘荷载与坡面渗水,滑坡运动方向与管道走向呈60°交角,根据现场地表裂缝发育特征认为滑坡为蠕滑拉裂型推移式土质滑坡。     

某项目煤破碎车间的滑坡治理

滑坡是指斜坡上的土体或者岩体,受河流、地下水活动、地震及人工切坡等因素影响,在重力作用下,沿着一定的软弱面或者软弱带,整体或者分散顺坡向下滑动的自然现象。滑坡是常见的地质灾害,往往造成重大经济损失和人员伤亡。     

西部沿海高速公路K21+060～K21+466段滑坡成因及治理

K21+060~K21+466段滑坡的坡体地下水丰富,虽经多次工程治理,但由于没有有效解决坡体的地下水作用,造成坡体依附于不利的地质结构面多次发生变形,且规模逐次增大,最终在特大暴雨的作用下形成了90×104 m3的大规模滑坡变形,严重影响了高速公路的正常运营。为有效治理滑坡病害,笔者依据对滑坡特点和成因的分析,制定了优先治水、支挡加固的滑坡紧急抢险工程和综合治理工程治理方案,并得以实施。根据多年地下水和滑坡位移监测显示,滑坡稳定性良好,治水结合工程加固的滑坡治理方案是有效的、可行的。     

深基坑工程施工中边坡支护效果监测分析

为了确保基坑支护施工效果，应做好现场监测方案的设计，包括坡面位移、边坡岩土含水量的变化、悬臂桩和坡体的变形等的监测。对桩身测斜管、桩间钢筋、桩间钢筋网、桩间土测斜管等进行监测。监测分析认为：该工程滑坡大变形与坡面渗漏有很大关系，一方面是排水管线的渗漏，再加上雨水的作用，引起了土体裂缝的扩展。     

深层圆弧滑坡作用下埋地管道有限元模型研究

针对埋地管道运输中出现的深层圆弧滑坡灾害问题,利用ABAQUS模拟有限元软件进行模拟计算,考察了坡角、滑坡规模、管道内压、管道壁厚对滑坡段埋地管道的影响。研究表明:当坡角、滑坡规模和内压增大时,最大Von Mises应力值也随之增大。坡角的改变对管道受力影响显著,坡角达到20°后,管道上部、中部和底部发生塑性变形;滑坡规模超过20 m时,应当采取保护措施保障管道安全运行。内压对管道所受最大Von Mises应力值的影响较小。该结论为深层圆弧滑坡作用下埋地管道的安全运行提供了理论依据。     

对渠道滑坡治理及质量控制的探讨

渠道滑坡是由于渠线经过地段地质、土壤条件差,开挖渠道后破坏了岸坡地层的自然平衡,加之在水的作用下而引起的。本文就这此介绍水利工程渠道滑坡的治理办法及防治措施。     

英坪Ⅱ号坑边坡稳定性弹塑性分析

以英坪Ⅱ号坑边坡为工程背景,利用FLAC3D分析边坡在开挖情况下的变形和稳定性,分析认为坡面和坡脚区域竖向位移最大,在坡脚的岩体产生向上的卸荷回弹位移;边坡的安全系数为1.34,边坡处于稳定状态;滑动面位置位于边坡的上部,并非发生整体滑坡,对于该部位可以进行相应的加固处理.     

滑坡的包络预测

本文针对滑坡监测资料在各观测周期之间摆动幅度较大的情况，对监测资料进行处理，建立灰色包络预测模型，预测坡体移动的区间，为滑坡治理提供可靠信息。     

印尼某工程滑坡分析及治理措施

位于印度尼西亚某地区的某工程滑坡场地周围地形以低山丘陵为主,地形地貌形态较复杂。分析介绍了该工程的滑坡诱因和计算过程,通过设置抗滑桩、锚索、分级放坡、卸载等措施解决滑坡问题,并要做好边坡排水设施。     

SECONDARY NUCLEATION OF ∊-CAPROLACTAM IN TOLUENE SOLUTION BY FLUID SHEAR FORCES

Qualitative analyses are developed to explain the role that surface viscoelastieity could be playing during the entrapment and displacement of residual oil. The characteristic time of a simple surface fluid, which is a measure of the memory of the interface for past stress-deformation behavior, is taken to be a measure of the degree of surface viscoelastieity. The approach taken is similar to that used by Slattery (1974, 1979), in two prior qualitative analyses of displacement.

The entrapment of residual oil in the smaller pores of an oil-wet rock would be enhanced by reducing the degree of surface viscoelastieity. We predict a similar effect during a free or forced displacement of oil by water in a water-wet structure. No conclusions can be drawn for a restricted displacement of oil by water in a water-wet rock.

For values of the interfacial tension less than the critical value, the rate of displacement of residual oil will increase as the degree of surface viscoelastieity is decreased.     

HDL Composition Regulates Displacement of Cell Surface-Bound Hepatic Lipase

HDL is able to displace cell surface-bound hepatic lipase (HL) and stimulate vascular triglyceride (TG) hydrolysis, much like heparin. Displacement appears to be a result of a high-affinity association of HL and apoA-I. HDL varies in its ability to displace HL, and therefore experiments were undertaken to evaluate the impact of HDL composition and structure on HL displacement from cell surface proteoglycans. HDL apolipoprotein and lipid composition directly affect HL displacement. ApoA-II and apoC-I significantly increase HL displacement from the cell surface. While changes in HDL cholesteryl ester and fatty acid content have no effect on HL displacement, increases in HDL phospholipid and TG content significantly inhibit HL displacement. HDL fractions from hyperlipidemic patients are unable to displace HL from the cell surface. These results indicate that the structure and composition of HDL particles in plasma are central to regulation of HL displacement and the hydrolytic activity of HL.     

EFFECTS OF SURFACE VISCOELASTICITY IN THE ENTRAPMENT AND DISPLACEMENT OF RESIDUAL OIL

Qualitative analyses are developed to explain the role that surface viscoelastieity could be playing during the entrapment and displacement of residual oil. The characteristic time of a simple surface fluid, which is a measure of the memory of the interface for past stress-deformation behavior, is taken to be a measure of the degree of surface viscoelastieity. The approach taken is similar to that used by Slattery (1974, 1979), in two prior qualitative analyses of displacement.

The entrapment of residual oil in the smaller pores of an oil-wet rock would be enhanced by reducing the degree of surface viscoelastieity. We predict a similar effect during a free or forced displacement of oil by water in a water-wet structure. No conclusions can be drawn for a restricted displacement of oil by water in a water-wet rock.

For values of the interfacial tension less than the critical value, the rate of displacement of residual oil will increase as the degree of surface viscoelastieity is decreased.     

The effect of adherend alignment on the behaviour of adhesively bonded double lap joints

For an adhesively bonded double lap joint, end mismatch between the two outer adherends can not be removed completely although it can be controlled within a manufacturing tolerance. This paper shows that the end mismatch introduces local bending and, consequently, results in a significant effect on the surface normal displacement. Furthermore, the end mismatch also affects the shear and peel stresses in the adhesive. To include the end mismatch effect, a modified equation is developed to characterise the peel stress in the adhesive layer in terms of the surface normal displacement measured using the holographic interferometry technique. The surface normal displacement predicted by the FEM is validated experimentally. A good correlation is also noted between the adhesive peel stress computed using the FEM and that calculated using the modified equation and the measured surface normal displacement.     

DISPLACEMENT OF A HYDROCARBON OIL FROM A METAL SURFACE USING A SURFACTANT SOLUTION

ABSTRACT

Separation of oils from solid surfaces is important in cleaning and degreasing operations. Water and oils are immiscible requiring the use of an additive which is miscible with water yet has an affinity for oils. Surface active agents, known as surfactants, have this property, being miscible with water while having an affinity for hydrocarbons. In some cases, surfactant solutions displace oils from a solid surface (i.e., remove oil by replacing the oil/solid interfacial area with surfactant solution/solid interfacial area). The presence of alkalinity as well as surfactant concentration is known to affect the ability of a surfactant solution to wet the solid surface and displace the oil. Experiments have been performed to determine quantitatively the effects of surfactant concentration and pH on the displacement of an oil from a metal surface. The displacement is measured in terms of the contact angle formed by the oil on the solid surface in the presence of the surfactant solution, the amount of time needed for the surfactant solution to cause part of the oil to detach from the solid surface, and the volume of the detached oil. Measuring the contact angle of the oil as a function of time shows that surfactant concentration and pH affect the displacement of oil from a metal surface. Increasing the pH of a solution of Triton X-100, a non-ionic surfactant, enhances oil displacement. Increasing the surfactant concentration also enhances oil displacement. The volume of oil which detaches from the solid surface increases with increasing pH and increasing surfactant concentration.

     

钢铁件浸镀铜的思考与实验

钢铁件浸镀铜一直受到人们的关注,其研究工作仍在不断进行,综述了浸镀铜的应用前景。分析了浸镀铜的实质。通过大量的实验研究,提出了对浸镀铜的要求、减缓置换速度的措施、抗氧化剂问题以及大生产中较难解决的问题,供同行在实践中参考。     

Finite-element and boundary-element analysis of craze micromechanics

The two numerical methods are used to estimate craze surface displacements and stresses for both isolated crazes and crazes at crack tips. The results are compared with the predictions of craze micromechanics models. The investigation includes the computation of the craze surface stress profile required to maintain a given craze opening displacement profile. The boundary element program requires less computer time than the finite element one, and similar results are obtained. The analysis also considers the craze surface displacement profile corresponding to an assumed craze surface stress distribution. The element methods produce results which are approximately the same as those obtained using the model of Verheulpen-Heymans and Bauwens.     

基于ESPI技术的混凝土单轴拉伸断裂特性研究

为了研究混凝土的拉伸断裂特性,对带有预制切口的C80高强混凝土棱柱体进行单轴拉伸试验,采用电子散斑干涉(ESPI)技术测量棱柱体表面的场位移等信息,分析加载过程得到混凝土的断裂参数以及断裂特性等。为进行对比分析,本次试验还采用线性位移计和夹式位移计测量试件的变形程度。对比结果表明ESPI技术的测量结果与夹式位移计结果吻合较好,证实了ESPI技术用于测量混凝土表面位移场的精确性和可行性。分析得到:初裂点应力约为峰值应力的82%;峰值下裂缝口张开位移(CMOD)为11 μm,结合公式得到混凝土在单轴拉伸下的断裂韧度约为0.41 MPa·m^1/2,断裂能约为24.71 N/m;利用两种拟合公式对试验应力-应变关系进行拟合,得到了较好的拟合结果。最后,通过不同加载步骤下ESPI技术测得的位移云图分析裂缝口张开位移随试件宽度的变化规律,得到了单轴拉伸下的裂纹扩展规律。     

A new method to measure adhesion and surface forces using a closed-loop accelerometer

A force-balanced MEMS sensor is developed to measure the forces between two surfaces with controllable distance. Its mechanical structure is like a pendulous micromachined accelerometer, and it is designed as a closed-loop system with electrostatic force feedback. The surface force on the sensor probe is balanced by the electrostatic force and the probe operates without displacement. This method avoids the displacement of the conventional cantilever, and the distance between the two surfaces is precisely controlled during the measurement. Experiments on surface force measurements between a probe surface and a ball surface are performed, and the attractive force and adhesion force between the two surfaces are measured under a precise distance controlled by a nanopositioner.     

机械镀锌的电化学沉积过程初探

采用体视显微镜观察了机械镀锌过程中锌粉在工件(Q235钢)表面的吸附和沉积过程,运用电化学的基础理论分析了金属锌粉的沉积机理。研究结果表明,基层建立阶段,锌粉和Sn2 发生置换反应;镀层增厚阶段,锌粉和M2 发生置换反应。置换反应使工件表面和锌粉颗粒表面之间产生库仑引力,导致锌粉颗粒在工件表面沉积。