RW水泥速凝早强剂在钻探护壁堵漏施工中的应用与研究

针对复杂地层钻进水泥护壁待凝时间长、效果差的问题,通过大量室内试验,进行复合速凝早强剂的配制,作为水泥护壁堵漏外加剂,投入多个矿区不同矿种钻探施工中使用,实现候凝时间短、凝结时间可控、效果好,经济效益和社会效益明显。     

矩形基础受垂直荷载作用下地基土中任意点的竖向附加应力系数计算公式

矩形基础受垂直均布荷载作用下,地基土中任一点的附加应力虽然可以通过角点法和应力叠加原理求得,但是除了矩形角点下各点计算较容易外,其余的点计算均较繁琐;矩形基础受垂直三角形分布荷载作用下,矩形基底面积垂直投影范围内地基土中各点的附加应力虽然可以通过角点法和应力叠加原理求得,但是除基底荷载分布为零的边的角点下各点计算较容易外,其余的点计算都很繁琐,而矩形基底面积外的点则无法计算。本文通过推导得出两个公式,借助电脑,能很容易地计算矩形基础受垂直荷载作用下地基土中任意点的附加应力系数,并通过计算对比,验证了公式是正确的。     

Uniform asymptotic Green's functions for efficient modeling of cracks in elastic layers with relative shear deformation controlled by linear springs

We present a uniform asymptotic solution (UAS) for a displacement discontinuity (DD) that lies within the middle layer of a three‐layer elastic medium in which relative shear deformation between parallel interfaces is controlled by linear springs. The DD is assumed to be normal to the two interfaces between the elastic media. Using the Fourier transform method we construct a leading term in the asymptotic expansion for the spectral coefficient functions for a DD in a three‐layer‐spring medium. Although a closed‐form solution will require a solution in terms of an infinite series, we demonstrate how this UAS can be used to construct highly efficient and accurate solutions even in the case in which the DD actually touches the interface. We compare the results using the Green's function UAS solution for a crack crossing a soft interface with results obtained using a multi‐layer boundary element method. We also present results from an implementation of the UAS Green's function approach in a pseudo‐3D hydraulic fracturing simulator to analyze the effect of interface shear deformation on the fracture propagation process. These results are compared with field measurements. Copyright © 2008 John Wiley & Sons, Ltd.     

丙脒盐酸盐的合成工艺研究

采用单因子实验及均匀实验设计，考察了影响丙脒盐酸盐收率的因素，经回归分析，得出了合成丙脒盐酸盐的优化工艺条件：物料配比n（CH3CH2CN）：n（CH3OH）：n（HCl）=1：1．1：1．1；整个反应体系为无水体系；在反应前期，溶液温度为0-10℃，pH值为4．0左右，反应时间为9h；在反应后期，溶液温度为0-20℃，pH值为8．0-8．5；氨-甲醇溶液的质量分数为15．0％。在此优化工艺条件下，丙脒盐酸盐的收率为94．0％，含量≥99％。     

Correlation in spectral accelerations for earthquakes in Europe

The shape of a uniform hazard spectrum has been criticized to be unrealistic for a site where the spectral ordinates of the uniform hazard spectrum at different periods are governed by different scenario events and conservative for long‐return‐period earthquake shaking. The conditional mean spectrum considering epsilon (CMS‐ε) takes into account the correlation of spectral demands (represented by values of ε) at different periods, to address these issues. This paper proposes new prediction models for the correlation coefficient of ε(T₁) and ε(T₂), a key component for developing a CMS, using Pan‐European earthquake records from a European ground motion database. Epsilon (ε) for each record is computed using the 2005 Ambraseys ground‐motion prediction equation. The model can be used to develop CMS for European sites, and it can be incorporated in the European seismic standards. Copyright © 2012 John Wiley & Sons, Ltd.     

The mechanism of energy loss and transition in a flow with submerged vegetation

The mechanism of energy balance in an open-channel flow with submerged vegetation was investigated. The energy borrowed from the local flow, energy spending caused by vegetation drag and flow resistance, and energy transition along the water depth were calculated on the basis of the computational results of velocity and Reynolds stress. Further analysis showed that the energy spending in a cross-section was a maximum around the top of the vegetation, and its value decreased progressively until reaching zero at the flume bed or water surface. The energy borrowed from the local flow in the vegetated region could not provide for spending; therefore, surplus borrowed energy in the non-vegetated region was transmitted to the vegetated region. In addition, the total energy transition in the cross-section was zero; therefore, the total energy borrowed from the flow balanced the energy loss in the whole cross-section. At the same time, we found that there were three effects of vegetation on the flow: turbulence restriction due to vegetation, turbulence source due to vegetation and energy transference due to vegetation, where the second effect was the strongest one.     

考虑开挖卸荷影响的桩侧摩阻力等效计算方法

基坑开挖后的卸荷回弹会导致桩侧摩阻力减小,但这一影响仅局限于基坑底部一定深度范围内。在计算开挖后的桩侧摩阻力时,可将卸荷视为作用在坑底的均布上拔荷载。当荷载作用在地表以下,土体附加应力应采用Mindlin应力解。定义基于Mindlin解计算开挖后桩侧摩阻力与开挖前变化为5%时的深度为开挖影响计算深度Hc,开挖深度和宽度对Hc的影响明显,土体内摩擦角的影响较小,而泊松比的影响可以忽略。据此推导出Hc的计算公式。开挖卸荷导致的竖向附加应力,Boussinesq解求得的结果大于Mindlin解,但随着深度增加,二者差异逐渐减小。分别针对开挖深度、宽度和内摩擦角不同取值的216种组合进行计算,结果表明,Hc范围内基于Mindlin解求得的桩侧摩阻力与基于Boussinesq解结果的比值? 最大为1.124,最小为1.001。工程实践中为偏于安全,可直接采用Boussinesq解进行桩侧摩阻力计算。     

大比例尺成矿预测中高精度立方格预测模型快速构建算法

立方格模型是一种常用的大比例尺三维可视化预测模型。在计算机三维图形学中,立方格模型又被称为块段模型,该模型比较适合表示非均匀体数据的空间分布,在矿山大比例尺深边部成矿预测、三维反演、矿山储量估算等领域得到广泛应用。目前,构建高精度立方格预测模型的一般方法是将已有地质体、地表、构造等三维地学对象进行栅格化。针对栅格化过程中遇到的2个关键问题,即体形的空间形态复杂和需要计算的长方体数量大（≥10⁶）,应用三维网格分割与种子填充（flood-fill）思想实现快速构建三维复杂体的立方格模型算法,其时间复杂度为O(n)。该算法的主要优点是花费相对小的空间代价高效地解决大量三角面与长方体的相交和空间查询计算问题。同时,应用该算法得到的立方格预测模型的长方体被划分为边界、内部和外部,便于开展预测要素综合模拟、矿山储量计算以及三维空间分析等其他后续地质应用。特别是将种子填充思想应用于高精度立方格模型构模,具有一定的创新性。本算法不仅适用于矢量体的快速栅格化,也适用于空间非自相交曲面（例如数字高程模型）的快速栅格化。     

软岩力学特性研究

本文讨论了软岩的基本特性。根据软岩的膨胀崩解耐久性、冻融作用、力学性质试验结果、, 分析软岩力学特性与赋存环境(含水量、地应力、温度)和时间的关系。总结了软岩的力学性质变化特征。并提出软岩强度取值原则。     

流动型态对曼宁糙率系数的影响研究

根据明渠水流流动型态的概念,通过对实验资料的分析,得到均匀流时糙率系数随水深增加而减小,形成M1型水面线的非均匀流时糙率系数随水深、水力坡度的增大而增大的规律。提出的糙率系数的二步计算法,可以解决因非均匀流水深沿程变化,难以建立糙率系数与水深关系的困难,为在水力计算中修正糙率系数提供了依据。