桩－土体系荷载传递特性和若干问题探讨

通过对大量的荷载传递测量资料进行分析，对桩与土体系荷载传递特性以及与之相关联的影响因素进行归纳总结；并基于荷载传递特性分析，对目前工程设计中若干不合理作法提出作者自己的看法     

土体的椭圆——抛物双屈服面模型及其柔度矩阵

本文证明了以经典塑性为基础的弹性模型的土体应力－应变柔度矩阵不能满足主对角线元素应占优的要求，为此作者提出了修正椭圆－－抛物双屈服面模型。     

某电厂煤港工程淤泥性土的工程特性研究

基于室内试验成果, 对台山电厂淤泥性土的分层、工程特性、ｗ 和ｅ 对主要物理力学指标的影响等方面作了较深入的分析, 对与淤泥性土的工程特性有关的岩土工程问题作了分析、评价。     

TWJ-1型土工试验微机采集处理系统的应用

ＴＷＪ－ １ 型土工试验微机数据采集处理系统的优势在于主机和采集仪两者合二为一, 其 功能为： 土工试验数据采集、土工试验数据处理、数据及成果的归档和管理、传感器标定及通 道测试。     

Effects of soil moisture stress on monoterpenes in loblolly pine

Monoterpene composition of xylem oleoresin in pole-size loblolly pine (Pinus taeda L.) was different between moisture-stressed and -unstressed trees during two test years. -Pinene concentration increased in stressed trees whereas -pinene, myrcene, and limonene decreased. Variations in camphene concentration with soil moisture stress were inconclusive. It increased with moisture stress in one test year and decreased in stressed trees during the other test year.     

Spatio-kinetic variation of methane oxidizing bacteria in paddy soil at mid-tillering: effect of N-fertilizers

Laboratory experiments were conducted to evaluate the variation ofpopulation size of methanotrophs (MOB) and CH₄ oxidation pattern inflooded rice soils sampled at three spatial points (rhizosphere, bulk and baresoils). Rhizosphere soil had higher MOB population size (301.1 ×10⁵ cells g^–1 dry soil) than bulk(37.2× 10⁵ cells g^–1 dry soil) andbare soil (19.1 × 10⁵ cells g^–1dry soil). The population size of MOB followed a decreasing trend with respectto fertilizer (urea NH₄NO₃ NH₄Cl control). The result indicated that rhizosphere soil presented thestrongestCH₄ oxidation activities, as shown by the highest values of the twokinetic parameters (K _m(app) andV _max). K _m andV _max increased significantly from bare to bulkto rhizosphere soil in control and fertilized soil and ranged from 6.2 to 133.2g g^–1 dry soil and from 0.03 to 0.41g h^–1 g^–1 dry soil,respectively. The differences in K _m andV _max among the three soils (rhizosphere, bulkand bare) in this study could be due to differential species composition ofmethanotrophic community and/or to conditioning of MOB under different soilmicroenvironments. The present study has demonstrated a competitive inhibition effectof NH₄ ⁺-N on CH₄ oxidation.     

岩土工程勘察中土工试验质量管理的探索

土工试验数据作为岩土工程勘察报告的重要依据,也是工程建设、设计的重要参数,土工试验的质量对工程总体的质量有着直接的重大的影响.本文针对迅速开放市场不完善的管理、体制、制度和行业的监管与之不相适应一些问题,重点剖析了土工试验人员的构成,针对不同条件、不同区域的土工实验室(或土工实验室中心)的人员组成,提出如何加强试验人员的专业培训和继续教育;同时就目前各类土工实验室(或土工实验室中心)的设备管理水平存在的问题,从设备管理、仪器更新和规范化、试验环境以及计量标定,资质认证等方面进行了综合分析,建议采取相应的措施,以确保土工试验数据的准确性;根据目前市场行业管理现状,阐述了在新的市场经济条件下,如何建立新的相适应的管理模式,如何加强行业监管等,有效地推行实验室的认证机制,确保土工试验数据的准确性,满足工程建设要求.     

基于粒子群和BP混合算法的土壤有毒重金属含量预测

利用当前重金属的含量去预测未来有毒重金属的含量,就可以采取有效的措施预防,对人们的健康有着重大意义.该文主要应用粒子群和BP混合算法的神经网络对甘肃某地区的土壤进行了预测,得到的预测数据和实际的基本相符,因此,该预测算法应用到土壤的预测中具有良好的效果,有良好的应用和推广前景.     

Effectiveness of single and coastal superposphates applied either in autumn or spring

Phosphorus (P) is known to leach laterally in water flowing during winter over pasture growing on flat soils that are shallow sands over slowly permeable lateritic ironstone gravel or clay soils in the high rainfall (> 800 mm annual average) areas of south-western Australia. The climate is Mediterranean, with hot dry December to March and cool wet April to November growing season, with excess water flowing over the surface from June to early-August. Fertilizer P is presently applied at about mid-March, near the start of the growing season. Single superphosphate has been applied for many years, which has a good residual value, and so the soils are no longer acutely P deficient. Consequently, a better method may be to apply the fertilizer at mid-August, after waterlogging and P leaching have usually receded, and radiation and temperature are rising, so pasture growth is increasing. The field experiment reported here was on a shallow sand over lateritic ironstone gravel where lateral leaching of P occurs. The experiment compared from 1990 to 1994 the effectiveness of single superphosphate (SSP), the fertilizer used at present, and coastal superphosphate (CSP), a partially acidulated rock phosphate containing about half the total P and one third the water-soluble P initially present in SSP. The fertilizers were applied annually either at mid-March or at mid-August. SSP applied at mid-March was the most effective treatment studied in the years when pasture plants had emerged before fertilizer was applied at mid-March. This is attributed to pasture plants being able to take up P from SSP applied at mid-March before leaching of P occurred, so that relative to SSP applied at mid-March, the other P fertilizer treatments (CSP applied at mid-march and mid-August, SSP applied at mid-August) were about equally or less effective. However, in years when the growing season had yet to start before fertilizer was applied at mid-March, then relative to SSP applied at mid-March, the other fertilizer treatments were equally or more effective. This is attributed to extensive leaching of P from SSP applied at mid-March, so that due to P losses from SSP applied at mid-March, the other treatments were equally or more effective. It is therefore concluded that profitable pasture production with reduced leaching is achieved by applying SSP at mid-March if soils are moist and pasture plants are growing at that time. However, if the soils are dry and no pasture plants are growing at mid-March, then CSP should be applied at mid-August.     

土钉墙的设计与应用

结合土钉墙的概念、特点及适用条件 ,就其作用原理、设计的一般原则和设计的方法作了介绍 ,同时为确保土钉支护方案的经济合理 ,提出了设计时应注意的几个问题。