不同降雨入渗条件下预应力锚索加固边坡稳定性分析

为了研究不同降雨条件下边坡安全系数及预应力锚索轴力变化规律,以省道S303沿线某边坡为研究对象,考虑土体饱和-非饱和渗流与非饱和强度理论,基于有限元分析,对不同降雨工况下的孔隙水压分布、锚索轴力及采用强度折减法计算的边坡安全系数变化规律进行了研究。结果表明: 降雨量一定时,降雨入渗范围随雨强增大而减小,暂态饱和区域随雨强增加而增大; 边坡在加固前后的安全系数均随降雨量增加而不断减小,采用预应力锚索加固能有效提高边坡安全系数,并减小降雨对边坡稳定性的影响; 随着降雨量增加,各锚索轴力均增大,当降雨量一定时,雨强越小,对应的锚索轴力提升幅度越大,靠近底部的锚索轴力对降雨最为敏感。     

A miniature triaxial apparatus for investigating the micromechanics of granular soils with in situ X-ray micro-tomography scanning

The development of a miniature triaxial apparatus is presented. In conjunction with an X-ray micro-tomography (termed as X-ray μCT hereafter) facility and advanced image processing techniques, this apparatus can be used for in situ investigation of the micro-scale mechanical behavior of granular soils under shear. The apparatus allows for triaxial testing of a miniature dry sample with a size of \mathrm{8}\hspace{0.17em}\mathrm{mm}\times \mathrm{16}\hspace{0.17em}\mathrm{mm} (diameter \times height). In situ triaxial testing of a 0.4–0.8 mm Leighton Buzzard sand (LBS) under a constant confining pressure of 500 kPa is presented. The evolutions of local porosities (i.e., the porosities of regions associated with individual particles), particle kinematics (i.e., particle translation and particle rotation) of the sample during the shear are quantitatively studied using image processing and analysis techniques. Meanwhile, a novel method is presented to quantify the volumetric strain distribution of the sample based on the results of local porosities and particle tracking. It is found that the sample, with nearly homogenous initial local porosities, starts to exhibit obvious inhomogeneity of local porosities and localization of particle kinematics and volumetric strain around the peak of deviatoric stress. In the post-peak shear stage, large local porosities and volumetric dilation mainly occur in a localized band. The developed triaxial apparatus, in its combined use of X-ray μCT imaging techniques, is a powerful tool to investigate the micro-scale mechanical behavior of granular soils.     

K0固结条件对上海软土强度和变形影响的试验研究

本文通过对上海淤泥质粉质粘土和淤泥质粘土,在K_0固结条件下的常规三轴和真三轴排水剪切试验,探讨了K_0固结状态对上海软土强度和变形性能的影响规律,并与各向等压固结三轴排水剪切试验的情况进行了比较和分析。     

粘土矿物对重金属镉的吸附研究

通过等温吸附试验，研究了粘土矿物膨润土、海泡石、凹凸棒石对Cd^2 的吸附情况，并与土壤对Cd^2 的吸附情况进行了对比。试验表明，几种粘土矿物对Cd^2 有很好的吸附作用，可用于重金属污染土壤的治理。pH值是影响吸附效果的一个重要因素。     

饱和与非饱和流溶质运移的试验研究与数学模拟

地下水污染系统，一般由非饱和带与饱和带两子系统组成，潜水面为两者的界面。已有的模拟试验多对其进行分段研究，认为污染物在系统中的运移规律为两者中的叠加。由于系统中存在界面过程和子系统间的相互作用，整个系统即饱和─非饱和带联合试验研究的结果较分段模拟结果更客观地反映污染物在系统中的运移规律；且这种联合研究在数学处理上也具有一定的优势。因此，饱和─非饱和流溶质运移的联合研究更值得重视。     

水下爆破技术在加固湿陷性黄土地基中的应用

分析了在湿陷性黄土区域，水下爆破技术在加固湿陷性黄土地基中的设计与实施。     

Reclamation of Abandoned Coal Mine Waste in Korea using Lime Cake By-Products

Abstract.  There are hundreds of abandoned coal mines in Korea's steep mountain valleys. Enormous amounts of coal waste from these mines were dumped on the slopes, contaminating streams with sediment and acid mine drainage. A limestone slurry by-product (lime cake), which is produced during the manufacture of soda ash, was investigated for its potential use in reclaiming the coal waste. The lime cake is fine grained, has low hydraulic conductivities (10^-8 to 10^-9 cm sec^-1), high pH, high electrical conductivity, and trace amounts of heavy metals. A field experiment was conducted; each plot was 20 x 5 m in size on a 56% slope. Treatments included a control (waste only), lime (CaCO₃), and lime cake. The lime requirement (LR) of the coal waste to pH 7.0 was determined; treatments consisted of adding 25, 50, and 100% of the LR. The lime cake and lime were applied either as a layer between the coal waste and topsoil or mixed into the topsoil and waste. Each plot was hydroseeded with grasses, and planted with trees. In each plot, soils, surface runoff, and subsurface water were collected and analyzed, and plant cover was measured. Lime cake treatments increased the pH of the coal waste from 3.5 to 6, and neutralized the pH of the runoff and leachate of the coal waste from 4.3 to 6.7. Moreover, the surface cover of seeded species was significantly increased; sufficient acidity in the coal waste was neutralized in the 25% LR plots to allow seed germination.     

厦门残积土的静动力学特性与震陷特性研究

用GDS应力路径三轴试验、振动三轴试验和振动台模型试验研究了厦门2种残积土的静动力学特性与震陷特性.发现花岗岩残积土具有剪缩特性,回弹体积模量随偏应力增大而显著提高;确定了花岗岩残积土的变形强度参数,并首次得到该土的液化曲线;建立了火成岩残积土的振动残余变形与模拟地震加速度及荷载之间的关系,并用其预估厦门填海地基的震陷量.     

成层地基非线性波动问题人工边界与波动输入研究

建立了考虑非线性效应的无限成层地基波动模拟的时域人工边界条件及相应的波动输入方法。首先，推导了线性阻尼介质中的一维人工边界公式，进而推广得到近似的二维人工边界方程：然后，通过等效线性化处理，获得了近似考虑远场成层地基非线性效应的人工边界：最后，建立了相应的波动输入方法。数值算例表明，所给出的人工边界与波动输入方法具有良好的精度，可以方便地应用于成层地基非线性波动问题的研究。