在东南亚原英联邦国家进行工程地质勘察应注意的几 点问题

随着中国经济实力的增加,越来越多的国内建筑和咨询设计企业将涉足海外市场,将面临与国内不同的机遇和挑战,本文通过介绍涉外工程-马来西亚槟城第二跨海大桥工程勘察过程中所出现的问题和情况,分析我国工程勘察行业在开拓海外市场时应注意和可能面对的问题。     

密云水库上游矿产资源开发对土壤环境的影响

通过对密云水库上游白河主要支流汤河、琉璃河流域和潮河流域内矿山开采现状调查,以及对区内采集的250件土壤样品测试成果,对区内土壤环境采用重金属总量分布特征、相关性分析法进行现状分析;并采用地累积指数污染评价、污染负荷指数评价和GIS空间分析等方法,开展矿山土壤环境影响现状评价,划分区内土壤污染范围,提出初步的治理对策建议。     

济南一次平流辐射雾的微物理结构及演变特征

受静稳天气影响,2017年1月3—6日我国华北、黄淮、长江中下游以及华南等中东部地区出现了大范围的持续性大雾天气,其中济南70 m以下的低能见度天气持续了6 h之久,最低能见度只有51 m。利用布设在山东省气象局院内的FM-120雾滴谱仪观测的微物理资料、自动气象站加密观测等资料,分析了此次浓雾天气过程的微物理结构,讨论了雾在4次\"发展—减弱\"过程中的主要特征,研究了雾在不同发展阶段以及爆发性增强期间的演变规律,探讨了雾的成因以及爆发性增强的原因。     

Palaeolimnological evidence for submerged plant loss in a floodplain lake associated with accelerated catchment soil erosion (Murray River,Australia)

Shallow lakes have been described as existing in two alternative equilibrium states, dominated by either submerged plants or phytoplankton. Causes of, often catastrophic, shifts between these states have been widely debated but may often result from displacement of the dominant community by stochastic influence. In Australian cut-off river meanders (also known as ‘billabongs’), anecdotal and palaeolimnological evidence suggests widespread loss of aquatic macrophytes since European occupation of the region c. post-1800. Our detailed and high-resolution stratigraphic study of a sediment core from Hogan’s Billabong (Murray River, Australia) seeks to identify the causes of the loss of aquatic macrophytes. Little direct evidence of the past extent and composition of submerged macrophyte communities was recovered. Nevertheless, results derived from other sediment proxies, including declines in the abundance of epiphytic diatoms and in plant-associated invertebrates, provide further indirect evidence of macrophyte disappearance. Despite limitations with radiometric dating, the sequence of events in the derived record suggests that a period of high abiotic turbidity, leading to a critical reduction in water transparency and caused by widespread erosion during the late 19th century, is the most likely factor contributing to loss of submerged vegetation from this billabong.     

Reinforcing a Dangerous Rock Mass Using the Flexible Network Method

Because the main failure type of a dangerous rock mass is collapse, the treatment of such a mass should focus on controlling collapse failure. When treating dangerous rock masses, disturbing the mass （e. g. by blasting） needs to be avoided, as this new damage could cause collapse. So the self-bearing capacity of the mountain mass must be used to treat the dangerous rock mass. This article is based on a practical example of the control of a dangerous rock mass at Banyan Mountain, Huangshi, Hubei Province. On the basis of an analysis of damage mechanism and the stability of the dangerous rock mass, a flexible network reinforcement method was designed to prevent the collapse of the rock mass. The deformations of section Ⅱ w of the dangerous rock mass before and after the flexible network reinforcement were calculated using the two-dimensional finite element method. The results show that the maximum deformation reduced by 55 % after the application of the flexible network reinforcement, from 45.99 to 20.75 ram, which demonstrates that the flexible network method is effective, and can provide some scientific basis for the treatment of dangerous rock masses.     

A concise parameterization of the hydraulic conductivity of unsaturated soils

The parameter n in the well-known expression for hydraulic conductivity K=K₀S_eⁿ (where K₀ is its value at satiation and S_e the effective saturation) is determined as a function of the exponent in the power form of the soil–water retention relationship. The result is validated with an extensive experimental database comprising some 43 soils, collected by Mualem.     

垦利县土地盐渍化及其发生变化趋势分析

垦利县位于黄河三角洲扇缘地区,具有典型的三角洲地貌。土地盐渍化是垦利县土地质量问题的根源,是影响土地生产力发挥的最根本原因。分析研究垦利县土地盐渍化发生的原因、现状及变化趋势,对指导当地土地资源的合理开发与利用具有重要的意义。     

华南亚热带山地土壤有机质更新特征定量研究

选择鼎湖山自然保护区森林植被带（SL）、灌丛一草甸过渡带土壤剖面（GC）进行薄层取样,根据土壤有机质^14C放射性水平,运用模型计算土壤有机质更新速率（m）。结果表明上部0－10cm土层有机质更新速率（m）最高;向下,m锐减;剖面下部m值极低,这说明土壤有机质由不同更新周期（T）组分构成。表层快循环组分占绝对优势,向下,慢循环组分为主,剖面下部为稳定组分。根据m、有机碳含量、有机碳含量、土壤容重、土层厚度计算有机质更新CO2产量,表层0－10cm层段CO2产量约为整个剖面的98％。SL剖面m值及有机质更新CO2产量均明显大于GC剖面相应值。分析表明在同一气候植被是制约土壤有机质更新及CO2产量的第一要素,这为通过绿化加强土壤碳汇功能提供重要依据。