粉煤灰增强回填碱渣工程特性的试验研究

碱渣与饱和卤水混合制成浆体回填到盐矿废弃盐腔可同时解决碱渣处理问题和地下废弃盐腔存在的地质隐患。回填碱渣强度是影响充填效果的重要因素。因此,为了提高回填碱渣强度,采用掺入粉煤灰制成复合碱渣对其强度特性进行改良。针对不同粉煤灰掺合比的碱渣开展了组成、力学和细观试验。研究结果表明：（1）掺入粉煤灰能明显改善碱渣的强度,使其黏聚力、内摩擦角都大幅提高,抗剪强度大幅增加;（2）粉煤灰掺合比越大,增强效果越明显,但强度并非随掺合比呈线性变化,对黏聚力而言,在0～20%内的掺合比下增加速度最快,而对内摩擦角则在20%～30%的掺合比区间增加最快,对抗剪强度而言,0～20%的掺合比内增加最明显;（3）粉煤灰掺入还可显著改善碱渣的压缩固结特性,使其固结系数大幅提高,从而提高碱渣固结速度,缩短充填工期,其中在0～10%的掺合比内对压缩固结特性改善最显著;（4）矿物组成分析表明,粉煤灰掺入改变了矿物组成,使得亲水性矿物含量急剧锐减,进而改变了其沉积特性。而细观分析则表明,粉煤灰掺入使碱渣从絮凝团细观结构变成了粉煤灰充当骨架的充填结构,且粒间支撑和拉联效应明显。从增强效果提高、压缩固结特性增强、控制成本和工期综合分析表明,最优掺合比为20%左右,建议工程中以不高于20%的掺合比作为实用掺合比即可取得较为理想的充填增强效果。该研究为揭示碱渣增强机制及废弃盐腔碱渣充填工艺优化提供了有益参考。     

某滑坡土体土-水特征曲线试验研究

利用能够控制基质吸力的4联式非饱和土直剪仪,对清江流域古树包滑坡滑带土体进行了不同固结应力条件下土-水特征试验,得出了土-水特征曲线并进行了函数拟合。结合土-水特征曲线拟合函数,经过数学推导确定了函数中各个参数的物理意义,建立了能够同时反映固结应力、基质吸力和含水率之间关系的函数表达式,弥补了其他方法不能考虑固结应力的缺陷,对补充和发展土-水特征曲线试验和理论具有重要意义。     

湘黔汞矿带旋扭构造动力作用与成矿规律

湘西黔东地区,在古生代沉积盖层中,北北东向保靖-铜仁断裂带的东侧,发育一系列北东向平移逆冲压扭性断裂构造带,它们均具有相似的变形特征和动力学机制,构成一个大型压扭性旋扭构造系统。旋扭构造控制了湘黔汞矿带的分布,其中北东向断裂带控制了汞矿带内各矿田的展布,而由北东向断裂带所派生的次级张扭性断裂裂隙带,则控制了单个矿体或矿床的产出和定位,特大型和大型汞矿床均产于旋扭构造的应力强区内。     

沿岸流非线性不稳定特征数值研究

当不稳定剪切波的波幅达到有限幅值之后,需要用非线性不稳定模型来分析沿岸流不稳定运动特征。本文通过建立并验证沿岸流非线性不稳定数学模型,在讨论该模型参数对沿岸流不稳定影响的基础上,率定实验中的模型参数并利用该数学模型模拟了实验中沿岸流不稳定的发展过程及其特征,主要结论有:（1）底摩擦系数越小,侧混系数越小,不稳定发生的时间越早,不稳定的波动幅值越大;（2）沿岸流非线性不稳定演化可能出现的5个阶段（线性阶段、倍周期阶段、大周期阶段、波群阶段以及不规则阶段）,实验中出现的沿岸流通常处于线性阶段或非线性倍周期阶段,倍周期阶段的涡旋是由线性阶段的涡旋发生追赶、配对直至合并产生的。涡旋配对以碰撞的形式发生,大部分能量转移至追踪波,然后以较慢的涡旋速度沿岸传播。     

Extensive-Dilatancy Anisotropy (Eda) Inferred From Observations of Crustal Shear Waves Generated By A Refraction Experiment In Northern Scandinavia

Summary. Particle-motion plots of shear waves have been studied for the section FG of the FENNOLORA seismic experiment. Shear-wave splitting is observed on some records and the polarization of the first arriving shear waves show two peaks at about N35°W and N65°E. These results can be interpreted as being due to crack-induced anisotropy with the crack direction dominated by a (dominant) horizontal stress around N35°W. This is consistent with in situ stress measurements and focal mechanism studies in Scandinavia. the results show that seismic refraction experiments may be useful in providing evidence of crack-induced anisotropy in the stable continental crust.     

A non‐coaxial critical state soil model and its application to simple shear simulations

The yield vertex non‐coaxial theory is implemented into a critical state soil model, CASM (Int. J. Numer. Anal. Meth. Geomech. 1998; 22 :621–653) to investigate the non‐coaxial influences on the stress–strain simulations of real soil behaviour in the presence of principal stress rotations. The CASM is a unified clay and sand model, developed based on the soil critical state concept and the state parameter concept. Without loss of simplicity, it is capable of simulating the behaviour of sands and clays within a wide range of densities. The non‐coaxial CASM is employed to simulate the simple shear responses of Erksak sand and Weald clay under different densities and initial stress states. Dependence of the soil behaviour on the Lode angle and different plastic flow rules in the deviatoric plane are also considered in the study of non‐coaxial influences. All the predictions indicate that the use of the non‐coaxial model makes the orientations of the principal stress and the principal strain rate different during the early stage of shearing, and they approach the same ultimate values with an increase in loading. These ultimate orientations are dependent on the density of soils, and independent of their initial stress states. The use of the non‐coaxial model also softens the shear stress evolutions, compared with the coaxial model. It is also found that the ultimate shear strengths by using the coaxial and non‐coaxial models are dependent on the plastic flow rules in the deviatoric plane. Copyright © 2006 John Wiley & Sons, Ltd.     

河南省西峡北部金矿分布特征浅析

从剪切带及原岩建造分析入手，论述了工作区内金矿的分布特征和主要控矿因素。区内的金矿床（点）无论其物质来源和时代如何，就其空间位置而言绝大多数金矿直接产在剪切变形变质带─—脆性及脆－韧性剪切带中。Ｆｅ／（Ｆｅ＋Ｍｇ）高比值的容矿岩石有利于金的沉淀富集。     

How Fast the Nucleus of Comet Hale–Bopp was Rotating?

At the First International Conference on Comet Hale–Bopp(Canaries, 1998) many astronomers agreed with the value of theperiod of axial rotation of its nucleus, which was obtained byobservers by a comparison of the two sequential patterns of thedust arcs. It was noted that the pattern had been repeated each∼12 hours. The value 11.35^h was taken as the periodof axial rotation. However, alternative periods of 4 and 8 days havealso been suggested. The possible reasons for thisdiscrepancy are discussed. It is shown that a short period could be obtained by a misidentification of the same arc on twosequential images and, as a result, an overestimate of theradial velocity of dust in the arcs. To obtain the half day period one must take the projected velocity of the arc ∼ 1.6 km/s,which exceeds the H₂O gas expansion velocity. If one takes a lower expansion velocity a longer period would be obtained.     

The role of current velocity in structuring eelgrass (Zostera marina L.) meadows

Measurements of velocity profiles, bathymetry, and surface sediment characteristics across eelgrass (Zostera marina L.) meadows yielded information on community development processes and functional attributes of this ecosystem. Height/length ratios of the meadows were positively correlated with tidal current velocity. Low, medium, and high current regimes were separated by surface current velocities of approximately 50 and 90 cm s^?1. Z. marina can tolerate approximately 120–150 cm/sec current velocities in the areas studied. Per cent silt-clay and organic matter content of the surface sediments are negatively associated with shear velocity, suggesting that meadows in high current areas are sources while meadows in low current areas are sinks of autochthonous detritus. Current velocity maintains seagrass meadows at different equilibrium levels (relative climaxes). We theorize these different equilibrium levels provide unequal habitat utilization potentials for the associated faunal community.