热轧宽带钢塌卷缺陷的分析与控制

针对莱钢1500mm热轧宽带生产线生产部分品种规格时出现塌卷缺陷的问题,分析了卷取张力、带钢断面形状、卷取温度、卷筒涨缩、助卷辊辊缝设定对卷形的影响,并提出了相应的控制措施,取得了较好效果。     

注水开发井套管的选择

分析了注水开发井套管损坏的特点;提出了解决注水开发井套管损坏的主要途径,即开发并合理选用高抗挤套管。选择高抗挤套管的具体方案是：对于2000m以内的浅井,既可以考虑在油层井段、注水裂缝地层段和油层以上的上覆岩层压力地层段使用抗挤油层套管,也可以考虑通井使用;对于3000～4500m的中深井,分为油层套管井段和各种岩层的封固段两种情况进行选择;对于5000-8000m的深井、超深井,分为油层套管井段、各种复杂地层的封固段、尾管段以及超深井多层套管柱4种情况进行选择。     

Non-destructive evaluation of cracks in massive concrete using normal dc resistivity logging

Discontinuities are one of the most harmful damage to the durability of concrete structures. Currents approaches are limited to assessments of surface damages, even if non-destructive methods appear to be effective for the detection and the location of cracks. That is why, these methods might be unsuitable for investigation of massive concrete body as dams and locks. Present works aim at the presentation of new results with electrical resistivity to study damages within concrete structures. In this article, the electrical resistivity focused on the study of cracks and discontinuities (concrete joints, interfaces…) in massive concrete structures by measurements done in preexisting boreholes. The used array is the normal dc resistivity logging. The study presents numerical and experimental results. First, modeling allows correcting experimental data. Then, development shows the sensitivity relatively to the discontinuity characteristics (aperture and the resistivity contrast between the discontinuity and the concrete). The tests on a real structure are carried out to define the methodology for on-site measurement. Results support the modeling.     

荔浦市岩质崩塌形成条件及失稳运动特征

通过对荔浦市境内碳酸盐岩区岩质崩塌及该区域地质环境条件的调查,总结了岩质崩塌的规模、发育高度、控制结构面等发育特征,分析了岩质崩塌形成条件,并判断岩质崩塌的失稳运动特征.本文以一处危岩为例,用无人机进行三维扫描并分析其形成原因及预测其失稳运动特征.     

HEAT TRANSFER ANALYSIS FOR A VAPOR BUBBLE

In this work, we review the basic heat-transfer mechanisms of a vapor bubble immersed in an unbounded and subcooled liquid. The governing equations for the vapor and liquid phases, together with appropriate initial and boundary conditions, are presented in dimensionless form. In particular, if the characteristic inertial times are smaller than the characteristic process times, the evolution for the radius of the bubble depends basically on the Jakob number, Ja, and the vapor densities ratio, ρ. Recognizing that the Jakob number is very large compared with unity, the resulting governing equations are modeled by a thermal boundary layer, adjacent to the radius of the bubble. We show that higher order corrections due to curvature effects, associated with conductive and convective heat terms of the energy equation for the liquid, characterize the collapse of the bubble. For different values of Ja and ρ, the numerical results for the evolution of the nondimensional radius of the bubble,a, and for the corresponding nondimensional temperature profiles, θ, show that the ending collapse state has a singular behavior, which we have denoted as a “thermal runaway.”     

齿形件精冲成形时的齿顶塌角分析及措施

针对精冲成形齿形件时的齿顶塌角问题,首先分析了齿形零件的几何特征及精冲成形特点,并分析了这些特征与齿形零件精冲时齿顶塌角的关系;将精冲变形区分为2个核心变形区和2个变形影响区,对核心变形区Ⅰ精冲塌角的形成过程进行了分析。然后,通过有限元模拟软件Deform-3D,找出齿顶塌角处材料在成形过程中的流动规律。结果表明:齿顶处A面轮廓附近的材料沿齿顶径向运动,一部分材料流向齿顶外侧;齿廓B、C侧附近的材料沿其轮廓线所指向的齿顶方向流动。再次,全面分析了影响精冲齿顶塌角大小的各种因素,找出压边力和反顶力对塌角大小的影响规律,得出反顶力比压边力对控制塌角的效果更显著。最后,提出了在齿形零件精冲成形过程中减小或消除齿顶塌角的具体措施对策。     

阳春硫铁矿疏干及地表塌陷

广东省阳春硫铁矿矿区水文地质条件复杂,围岩富含岩溶水,为整治地下涌水,采取了一系列措施对井下和地表进行治理。详细介绍了生产疏干放水与地表塌陷的情况,对存在的问题提出了探索性建议。     

超高压水射流中空化现象对轮胎破碎作用研究

为了探讨超高压水射流破碎轮胎过程中,冲击波和微射流的作用机理,基于FLUENT软件环境,采用VOF模型求解Navier-Stokes方程,数值模拟了近壁面的空泡溃灭过程,结果表明,射流冲击物面时,空泡溃灭产生的压力脉冲远大于微射流产生的冲击压力。结合超高压水射流破碎轮胎试验,通过对胎面胶的切槽断面形貌进行观察,研究了微射流和冲击波对橡胶材料的破坏作用,认为橡胶材料在受到空化作用破坏时,表现出明显的冲击脆化现象,微射流在材料壁面冲击出边缘齐整的针孔状形貌,冲击波引发材料产生拉伸破坏。     

降雨作用下土体细颗粒迁移特征及其对崩塌的影响

为了研究坡面土体崩塌的时空特征,进行了人工降雨水槽实验,在不同降雨强度下,观测了土体细颗粒的迁移、土体崩塌的时间序列和相应的孔隙水压力变化曲线,并对崩塌体、迁移土体和渗流浆体进行序列取样。实验结束后进行了土体颗粒分析,并结合标度分布参数,对比了坡面相同位置不同深度实验前后颗粒级配的变化,从随机性的角度分析了土体颗分参数与强度之间的关系。结果表明：在降雨作用下,坡体中的细颗粒会发生迁移,使土体结构发生改变。细颗粒在某一位置集聚,引起孔隙水压力增大;在水力梯度较大和细颗粒容易积聚的区域,更容易发生坡面崩塌破坏;坡脚处流出的细颗粒波动越大,坡面崩塌现象越明显;土体的剪切强度和内摩擦角随细颗粒含量的增大而减小;坡面土体颗粒的空间分布决定了土体强度的空间分布,坡面土体剪切强度和内摩擦角均具有Weibull随机分布特征,最终导致坡面土体的崩塌在时间和空间上呈现随机性。     

水基钻井液用阳离子型封堵剂的合成及性能

以苯乙烯（St）、丙烯酸丁酯（BA）及阳离子可聚合单体,利用乳液聚合方法制备水基钻井液用阳离子型封堵剂,采用红外光谱分析了封堵剂的结构特点。泥球浸泡实验结果表明,质量分数为5.0%的阳离子型封堵剂乳液和饱和盐水抑制黏土水化性能相当。评价了阳离子型封堵剂对CaC12无土相钻井液性能的影响。结果表明,加入质量分数为2.0%的阳离子型封堵剂,可将CaC12质量分数为25.0%的无土相钻井液的高温高压滤失量（120～130 ℃）控制在10.0 mL左右。