防洪堤施工中筑堤粗粒土控制干密度的合理性分析

文章对相对密度控制问题进行分析,并提出几点建议。     

用振动挤淤法处理标准海堤的软土地基

以淤泥类软土的动力特性为基础发展起来的振动挤淤法，在标准海堤软土地基处理中有其独特的实用性。根据海堤的工程特点，分析了振动挤淤法在处理海堤软土地基的必要性和可行性。并着重阐述了振动挤淤法中3个关键施工参数的理论分析和工程实践，这3个参数包括：基础埋深，最小垫层厚度，施工机械作业参数。     

河道堤防设计高程的概率设计和风

介绍河道堤防设计高程的概率和风险校核方法。该方法综合考虑多种不确定性因素的影响，利用随机微分方程推求河道水位的概率分布，并对风浪的随机影响进行分析，按照随机可靠性理论，对常规采用确定性方法确定的河道堤防高程进行漫顶风险校核和可靠性设计。     

大直径现浇混凝土薄壁筒桩围堤技术

介绍了大直径现浇混凝土新型筒桩结构围堤，与目前常用的几种围堤方法相比，从设计计算理论、经济指标、施工特性、结构特性、使用功能、土地利用和环保及景观七个方面进行了比较，突出了该新型堤的优越性，并介绍了该围堤的施工工艺。     

南洞庭湖洲垸土壤中四种重金属的分布特征及污染状况评价

对南洞庭湖10个洲垸地点的土壤进行了4种重金属Cd、Pb、Cu、Sb含量的测定与分析,并运用地积累指数法对每种重金属的污染状况进行初步评价,结果表明,重金属Cd的污染普遍较为严重;重金属Pb未达到明显的污染水平;重金属Cu的污染程度虽较轻,但需控制其发展;重金属Sb在某些地点污染较严重,其分布规律呈现较强的不均衡性。     

Soil conservation on road embankments using palm‐mat geotextiles: field studies in Lithuania

The application of geotextile mats constructed from the palm leaves of Borassus aethiopum (Borassus) and Mauritia flexuosa (Buriti) was investigated in field experiments. The use of geotextiles caused improved soil moisture storage during dry summer periods on a steep (21–25°) roadside slope in Lithuania. The enhanced soil moisture under the Borassus and Buriti mats encouraged better root development of perennial grasses, increased the number and weight of earthworms and increased the dry biomass of perennial grasses by 50.5 and 18.2%, respectively, compared with a grassland control. The mean rate of water erosion from bare soil during the study period from 17/04/2007 to 11/12/2008 was 33.21 Mg/ha. The cover of palm‐mat geotextiles decreased soil losses from bare fallow soil by 94.8–91.1%. An erosion rate of 0.85 Mg/ha over this 21‐month period was measured on the slope under perennial grasses without geotextile cover. Application of geotextile cover on perennial grasses completely prevented soil erosion by water. Therefore, use of geotextiles has clear soil and water conservation benefits on industrial slopes susceptible to erosion. The use of geotextiles has multiple benefits including soil conservation, the improvement of plant growth conditions and the encouragement of earthworm populations.     

塔里木河干流中游输水堤防对生态保育的影响

通过对塔里木河中游地区输水堤防修建后,有生态闸和无生态闸断面地下水位、水质和生态变化监测,结果发现:在有生态闸断面的地下水埋深、地下水矿化度都保持在理想范围内,而无生态闸断面的地下水埋深持续下降,地下水水质变化呈恶化趋势,由于生态对环境变化的迟滞性特点,有无生态闸断面的植被盖度尚未表现出明显的分化,但由于沙子河断面地下水埋深的增大,一些草本植物逐渐消亡,而乌斯满断面物种则无变化。因此,有必要采取措施防止堤防外的生态退化,促进全流域生态系统的健康发展。     

城市景观水系中的生态驳岸研究

从保护生态以及满足人的视觉和心理需求出发,探讨了发展生态驳岸的重要性和可行性。     

3-D Dynamic Response of Reinforced Embankment and Track System Subjected to Moving Traffic Load

An analytic method was used to study the dynamic response of track system on reinforced embankment subjected to moving traffic load. Based on Biot's dynamic poro-elastic theory, dynamic analytical model of track system and reinforced embankment was established. The rails were described as an infinitely long Euler beam subjected to moving axle loads and sleepers were represented by continuous mass. Reinforced embankment embedded between track system and poro-elastic subsoil was modeled as a transversely isotropic layer. Subsoil was fully saturated poroelastic medium governed by the Biot's theory. Using the Fourier transform, the governing equations were then solved analytically in the frequency-wave-number domain. The time domain responses were obtained by the inverse Fourier transform computation. The influences of the train velocity, thickness of reinforced layer, load amplitude and reinforcement's ratio on the displacement responses of rails were carefully investigated. Computed results show that the vertical displacement of rails increases with the increase of load speed initially and decreases later. The displacement of rails with reinforced embankment is less than the ones without reinforced embankment. The displacement of rails increases with the increase of load amplitude and decreases with the increase of reinforcement's ratio.     

白山金矿尾砂堆积坝坝体静力、动力稳定分析研究

本研究选用吉林省白山金矿尾砂堆积坝为目标,对其坝体静力、动力稳定进行分析,以其为细粒尾矿筑坝稳定性研究提供借鉴。试验结果表明,静力稳定的安全系数和动力稳定的安全系数均大于规范规定的安全系数值,所以可以认为在静力、动力情况下,吉林省白山金矿尾砂堆积坝坝体均能保持稳定。