土工实验中的液、塑限测定浅议

文章分析了当前土工实验中的液、塑限测定过程中应当注意的问题及其存在的问题,并论述了如何对其实验数据进行处理和分析的方法。     

Social capital and soil conservation: evidence from the Philippines*

The formation of social capital is hypothesised to enhance collective efforts for soil conservation. The Landcare Program in the southern Philippines promotes simple conservation practices in upland environments by supporting community landcare groups and municipal landcare associations, thus augmenting social capital. A study was conducted in 2002–2003 to evaluate the Landcare Program, using a mix of quantitative and qualitative techniques. In the present paper, the relationship between social capital formation and adoption of soil conservation in the Municipality of Lantapan is investigated. It is concluded that the Landcare Program as a whole created a valuable stock of bridging social capital, rapidly accelerating the adoption of contour farming measures, but that on‐going support is needed to maintain this capital stock.     

Analysis of nutrient content and assessment of economic value for major salt-tolerant plants in coastal areas: a case study of Dongying City,Shandong Province

Salinization of soil is a worldwide problem concerning resources and ecology,especially serious in coastal areas.Testing of 26 sorts of data or parameters are carried out on leaves of 22 plant species (in 24 plant variety) of existing main salt-tolerant plant of the Yellow River Delta region.Data or parameters include the following elements:contents of K+,Na+,Ca2+,Mg2+ and Cl-,contents of protein,fat,total energy,ash and contents of 17 amino acids.The results show that these tested plants have economic values.For example,according to their uses,they can be divided into edible plants,forage plants,medicine or health plants,and some of them can be used for multipurposes.These plants have played important roles in the sustainable utilization of plant resources in coastal areas.This paper has taken evaluations on the economic uses of salt-tolerant plants and given suggestions for saline soil improvement and resource utilization in coastal areas.Based on the results of investigation and experiments,we suppose that the salt-tolerant plants in coastal areas can be grouped into 9 main groups according to their eeonomic value:pioneer plants for saline land improvement,medicine,edible and forage plants,industry material forestation,breeding material,energy plants and eco-tourism resources.     

浅析公路桥梁软土路基处理的技术要点

从已建软土地基上公路运行情况看,工后沉降较大,容易造成"桥头跳车"现象,轻者影响行车速度,损害车辆,严重的导致交通事故,造成人员伤亡。所以,选择合理的软基处理方案及方法快速实施,从而取得预期的经济和社会效益,就具有重大的实际意义。在本文中,笔者对公路桥梁软土路基处理的技术要点提出了自己的几点看法。     

钢板桩围堰在水位变动区和软弱地基中的应用

利用钢板桩作围堰,在水位变动区和软弱地基条件下,采取一定刚度的围护设施来满足深基坑的施工需要;成功地运用了一种既施工简便、节约材料又确保安全的围护结构。根据软土的特点和钢板桩的柔性特征,通过采用模拟基坑开挖过程,按照板桩墙围护结构的设计计算方法进行围堰设计,并通过实际施工中一定的控制措施和对围堰内力、变形监测,确保相邻建筑物和自身结构施工的安全。根据实际运用的效果监测表明,采用的钢板桩围堰,是可行而又较优的一种方案。     

氢化物发生-原子荧光光谱法测定痕量硒

研究了氢化物发生-原子荧光光谱法测定土壤和水样品中的痕量硒,系统地考察了HCl浓度、KBH4浓度的影响;确定了最佳测定条件;共存元素的影响及干扰的消除,硒的回收率为95%～102%,硒的检出限为0.18ng/mL,RSD小于4%。本法用于测定标准土壤和水样品中的硒,结果与标准值吻合。     

黄土高原生态环境建设与土壤质量演变

土壤质量高低对植被恢复具有重要作用，它不仅影响植物群落的发生、发育和演替的速度，而且也对生态系统过程、生产力和结构等具有重要影响。植物演替过程．也是物种对土壤肥力逐渐适应、改造及不同物种在不同肥力梯度下相互竞争和代替的过程。因此，植被恢复过程也从多个方面影响着土壤质量，植被是土壤质量改善的重要驱动力之一。黄土高原地区实施退耕还林还草后土壤质量将在某种程度上得以恢复．不同类型植被土壤质量恢复还具有明显差异，并且在一定时间范围内，随恢复时间延长，土壤质量不断改善。     

我国西南地区水土治理及西部大开发的实证研究

无论是从问题的实质,还是方法论的角度来讲,水土治理都是西南地区经济开发中的一项战略性工程。通过对云南省红河州具体的水土流失现状、危害和治理的紧迫性和治理中存在的主要问题的分析,提出了西南地区水土治理的总体战略设想和具体的治理措施。     

山东省水土流失经济损失与生态价值损失评估

介绍了山东省水土流失现状，分析其危害，重点探讨了水土流失经济损失和生态价值损失的计算方法，建立经济损失计算模型，提出水土流失生态一经济面积边际比的概念，计算山东省县域边际损失比，并对其进行区域分布规律分析。     

基于数字图像的顶管施工土层移动模型试验

为研究顶管施工土层的变形和移动规律,利用数字图像方法观测,建立了顶管施工土层移动模拟的物理模型,研究了顶管土层损失引起的上覆土层变形和移动规律,获得了如下结论:1)顶管施工地层损失引起顶管周围土体向顶管移动,最大变形发生在顶管周围;2)顶管地层移动从顶管周围向地表上方以一定角度传递和扩散,地表沉降范围大于顶管直径,顶管地表变形呈漏斗状,最大沉降在顶管的正上方;3)可以运用随机介质理论和概率积分法预测顶管施工地表变形;4)可以数码望远镜代替相机,采用数字图像方法观测顶管地表建筑物的非均匀变形。