APPLICABILITY OF SEDIMENT TRANSPORT FORMULAS

1 INTRODUCTIONThe selection of aPPropriate sediment transport fOrmulas under different flow and sedfornt conditions isimPoftant tO the sedimen tusPort and river morphologic stUdies of a river. There are numrousWlas published in professional joumals and summarized in sediment transPort texthooks. Mosttextbooks shy away from direct comPallsons of the accuracies of transPort formulas. ComPllted resultsbased on differnt transport formulas may differ significanly from each other and from …     

我国陆地均匀重力测量补点问题的研究

推导了重力布点公式，应用全国重力点检验了原有代表误差系数的可靠性，估计了我国目前和将来5′×5′平均高的精度，阐述了陆地重力测量布点系统的建立方法和应用方法，给出了我国陆地重力点补测方案，应用它即可确定我国陆地每个5′×5′内应补测的重力点数及其分布。     

热力学基本关系式和化学势及过程的不可逆性浅析

本文从可逆过程有最大功出发，分析热力学基本关系式的适用体系，说明了化学势和过程不可逆性的物理意义。     

秦巴地区次生金异常地表含矿性判别及矿体定位估算

在分析金粒在水系中运移、落淤和在土壤中扩散动力条件的基础上,本文建立了五万分之一水系沉积物测量金异常地表含矿性的判别公式,阐述了推算异常内矿石最高金品位的方法并计算了秦巴地区的判别指数;总结出万分之一土壤测量矿致金异常的标志特征、矿体定位的估算公式及各级次地形坡度角的系数和常数。这些公式、方法,有较大的实用意义。     

"海马"牌配合饲料喂养大黄鱼的试验

本文笔者于2000年5月17日至7月5日在霞浦海区网箱养殖大黄鱼中，进行"海马"牌配合饲料(按不同比例搭配小杂鱼)喂养大黄鱼试验.结果表明在相同的管理和养殖条件下，10％幼鱼粉搭配90％小杂鱼、50％幼鱼粉搭配50％小杂鱼、膨化饲料搭配小杂鱼在提高大黄鱼的生长速度、存活率和降低养殖成本方面均优于单一使用小杂鱼.     

Finite-element computation of wave impact load due to a violent sloshing

A nonlinear sloshing problem is numerically simulated. During excessive sloshing, the sloshing-induced impact load can cause a critical damage on the tank structure. Recently the problem becomes an important research topic in LNG (Liquefied Natural Gas) Tanker and FPSO (Floating Production Storage Offloading) design. In this study, the wave impact load on the structure is obtained numerically by imposing the exact nonlinear free surface conditions and compared with that predicted by Morison's formula. As a theoretical model, a three-dimensional free surface flow in a tank is formulated in the scope of potential flow theory with the exact nonlinear free-surface conditions. A finite-element method based on Hamilton's principle is employed as a numerical method. The problem is treated as an initial-value problem. The nonlinear problem is numerically solved through an iterative scheme at each time step.     

Numerical Study on Breaking Criteria for Solitary Waves

Studies of the breaking criteria for solitary waves on a slope are presented in this paper. The boundary element method is used to model the processes of shoaling and breaking of solitary waves on various slopes. Empirical formulae that can be used to characterize the breaking of solitary waves are presented. These include the breaking index, the wave height, the water depth, and the maximum particle velocity at the point of breaking. Comparisons with the results of other researches are given.     

任意曲线边界条件下缓变水深水域波浪传播的数值模拟

缓坡方程被广泛地应用于描述波浪的传播变形计算,目前一般采用矩形网格求解.将计算域剖分为任意四边形网格,以格林公式为基础,在变量沿单元边界线性变化的假定下,对双曲型的波能守恒方程、波数矢无旋性方程进行离散,同时通过等参单元变换推求节点偏导数值以离散椭圆型光程函数方程,从而建立了任意曲线边界条件下缓变水深水域波浪传播的数值模拟模型.将模型应用于平行直线型等深线地形,并将计算域剖分为不规则四边形网格,对不同入射角、底坡、波高等多种组合情况比较了数值解与解析解,结果表明两者一致.应用于复杂边界的实例,数值模拟结果与物模实验值基本吻合.     

Engineering behaviour of MICP treated marine clays

Abstract

In the present scenario, with much focus on sustainable development worldwide, Microbially Induced Calcite Precipitation (MICP) is a promising biological soil improvement technology. However, only very limited research is reported on the effectiveness of this technique in marine clays. This paper presents the salient features of an experimental study conducted on two typical marine clays stabilised by MICP. Effectiveness of the technique was evaluated through a series of one-dimensional consolidation tests, unconfined compression tests, and index property determinations. It is found that biostimulation approach is not effective in marine clay; bio-augmentation is needed for soil improvement. Bio-augmentation results in the reduction of liquid limit and plasticity index to about 29% and 47%, respectively for the marine clays. A comparable improvement in volume change behaviour is also observed. There is a marked increase in undrained shear strength, upto about 148%, of MICP treated marine clays at toughness limit water content. Curing is also found to have a significant role in soil improvement. The observed transition in the nature of the tested marine clays from that of fat clay to elastic silt suggests the potential of the proposed approach. An empirical equation is also proposed to predict compression index of MICP treated marine clays.     

风浪场波生横向彻体切应力的分析

使用风浪经验公式和风浪传入近岸的小振幅波动理论计算并分析了地转条件下波生横向彻体切应力随风速、风区、水深等因素的变化规律。结果表明，彻体切应力随风速、风区的增大而增大，直到波浪达到完全成长状态，但增长速度并不规则；为更加直观的显示彻体切应力的海流驱动作用，将其与定常Ekman漂流中的风生湍粘性力进行了有意义的比较，结果表明，在中、高纬度的通常海况下两者具有相同量级，因此，在有波浪场存在的条件下，由风、浪共生海流的总体强度将比理论Ekman漂流大，并且不会完全符合Ekman漂流理论的转向规律，在表层尤其明显。由此说明，在一定情况下在风生漂流研究中考虑由地转引起的波生横向彻体切应力是非常必要的。