城市原生污水源热泵系统干渠取水分析

介绍了城市原生污水源热泵系统干渠取水工艺,给出了干渠开口方式及其水头损失计算方法,分析了重力流流量与引水管坡度等参数的关联关系式,指出了理论水深和实际水深的区别,推导得出了实际水深与开口位置、引水管位置参数的关系式,并进行了示例设计。研究表明,开口处流速宜取1.5~2 m/s,开口处的水头损失在180~330 mm之间,引水管的坡度应根据流量、管径和实际水深确定。     

管壁粗糙度对室内排水立管临界流量的影响

近年来,由于建筑排水方面塑料管的推广使用,管壁粗糙度对排水立管临界流量的影响问题,引起了普遍的关注.本文通过两相流理论分析和水力学试验验证证实:室内排水立管管壁粗糙度的减小,不仅不能加大其临界流量,反而会减小其临界流量.     

流态混凝土的工程应用研究

介绍了高性能流态混凝土的配制方法、坍落度试验数据与结果、抗折强度试验数据与结果、变形性质试验数据与结果以及耐久性试验数据与结果,为流态混凝土在路面工程中的应用做出了积极的探索.     

侧向流曝气生物滤池水力混合特性研究

从反应器理论出发,采用脉冲刺激响应技术对新型侧向流曝气生物滤池进行了流态试验。对液龄分布函数的数据统计得出,无因次方差σθ^2在0．12～0．20,P。准数在8～15,说明反应器流态介于全混流和平推流之间,偏于平推流。根据试验结果,运用轴向扩散模型建立了滤池的流态模型。进水流量和曝气量是影响LBAF水力混合特性的重要因素。曝气和增加进水流量有利于减少反应器的返混程度,使反应器的流态更接近于平推流。经理论分析认为,该流态有利于生物种群的空间分布,保证了反应器的容积利用率,提高了处理效能,是一种较好的流态形式。     

盖板对泄洪隧道急流弯道水利特性的影响

采用物理模型实验与三维数值模拟相结合的方法,对采取盖板控制法后的泄洪洞明流弯道水力特性展开了研究,并与未设盖板情况进行了对比。结果表明:设置盖板后,弯段及下游直段水流流态得到改善,弯道两岸及出口水深分布更加均匀,下游直段水流表面波动明显削减,大流量情况下水流流态改善效果更加显著,下游直段水流表面波动更平稳,两岸水深超过直墙的现象消失;弯道流速分布更加均匀,凹凸两岸流速差值降低,平面流场分布更加均匀;底板压强随泄流量的增大而增大,设置盖板后压强增加,弯道出口处压强减小且分布更加均匀,验证了泄洪隧洞急流弯道段设置盖板工程措施的合理性。研究成果可为弯道的流态改善措施提供新思路。     

圆形截面冷却塔不同表面粗糙度时绕流特性的试验研究

以双曲型圆截面冷却塔的风荷载模型为背景,探讨了高雷诺数模拟的途径,采用改变模型表面粗糙度和调整风速的手段,获得了在较低雷诺数条件下模拟高雷诺数流态特性的试验条件。研究了不同粗糙度表面的截面绕流特性,得到了一些宝贵的试验数据和有益的结论。     

基于示踪试验的清水池水力效率影响因素研究

以优化清水池运行条件、提高水力效率为目的,通过建立中试模型进行不同工况下示踪试验,研究水深、流量、停留时间和穿孔挡板对清水池水力效率的影响。结果表明,在合理取值范围内,水力效率随着流量的增加而增加,随着水深、停留时间的增加而减少,水力效率随流量和水深的变化趋势均类似抛物线;对于停留时间较大的清水池,在进出口和廊道拐角处增设穿孔挡板可明显改善水体流态,提高水力效率,穿孔率为10%的穿孔挡板比无穿孔的挡板水力效率提高了13%~20%。     

道路雨水口布设方案对泄流能力影响的模拟研究

雨水口作为城市排水系统的重要组成部分，其布设情况对周边小区及道路积水的消除至关重要。为此，利用耦合了水文和水动力过程的数值模型，研究雨水口在不同道路纵坡坡度、布设数量和径流流量条件下的泄流能力。结果表明，道路纵坡坡度越大，雨水口的泄流能力越差，在小流量、雨水口数量为5个（间距为20 m）的条件下，当道路纵坡坡度从0.3%增至8%时，雨水口泄水率从55.64%降至21.05%；雨水口数量越多，其泄流能力越强，在小流量、道路纵坡坡度为0.3%的条件下，当雨水口数量从2个增至5个（间距由50 m降至20 m）时，雨水口泄水率由25.60%增至55.64%；径流流量越大，雨水口的泄流能力越差，在道路纵坡坡度为0.3%且布设5个雨水口的条件下，小、中、大3种流量下雨水口泄水率分别为55.64%、46.92%、37.28%。     

ABR反应器的水力特征研究

采用LiCl示踪法对厌氧折流板反应器(ABR)在不同奈件下的水力特征进行了研究。结果表明，ABR是一种各格室趋于CSTR流态而整体趋于推流流态的复合流态反应器。进水有机物浓度及HR丁对水力流态均有影响，而前者为主要因素。进水有机物浓度越高则各格室的混合流态越好。ABR可在较低的上升流速下运行。当各格室去除有机物量相同时，HR丁越长则其混合流态越趋于CSTR流态。进水底物浓度较低时，反应器的分格数宜控制在3～4格；进水底物浓度较高时，宜将分格数控制在6～8格。     

城市道路排水口不同体型设施的模型实验与选择

在分析我国市政道路雨水口篦子设置现状及存在问题的基础上,采用断面模型试验,从流态、过篦流量及设置坡度三方面试验了0°栅条、30°栅条、45°栅条及90°栅条篦子的排水特性,并提出了城市道路排水口不同体型设施的选择与建议,以期为市政道路设计等相关人员提供参考和借鉴。     

Detection of critical road roughness sections by trend analysis and investigation of driver speed interaction

Pavement roughness (IRI—International Roughness Index values) influence the stability of traffic movements both on intercity roads and urban roads. This study is to determine the exact locations of critical pavement roughness values that affect traffic motion stability and comfort in city centre highway arteries. Roughness data with 10 m intervals were collected on a 3140 m divided road containing three consecutive signalized intersections in the city centre arterial. These data were analysed using the distance-dependent Mann-Kendall trend analysis method and checkerboard model. The sections where roughness is important were determined at a 95% confidence interval. The results will show where future pavement improvements should be prioritized for municipalities and road maintenance engineers and will form a basis for the urban road management system.     

城市道路沥青路面平整度影响因素及对策探讨

路面平整度是路面评价及路面施工质量验收中的一个重要指标,主要反映的是路面纵断面剖面曲线的平整性。本文从多个环节分析了影响城市道路沥青路面平整度的主要因素,提出了相应的技术对策及可行措施。     

西藏林芝地区冰川降雨型泥石流起动实验初步研究

 近年来,由于全球气温升高,导致西藏地区泥石流暴发频率增加,其中包括冰川降雨型泥石流灾害。以西藏林芝地区的冰川降雨型泥石流为研究对象,首次通过观测冰川降雨型泥石流起动过程中水位、孔隙水压力等变化特征,得到水位、孔隙水压力与堆积坡度、堆积厚度的关系以及沟道物质起动特征,根据水位、空隙水压力的时间变化特征,得到不同试验条件下水位与孔隙水压力的相互关系。通过相似物理实验,分析实验过程中流量、流深、流速等参数与泥石流堆积坡度、堆积厚度的关系,并将冰川降雨型泥石流起动分为前期饱和阶段、起动阶段、堆积阶段。由相似比得到研究区典型冰川泥石流起动的流深、流速等野外观测结果与实验结果与一致,为研究区冰川降雨型泥石流的研究提供参考。     

The influence of combined vegetation stalk thickness on water flow resistance

Vegetation that exists in the natural environment often involves a combination of plants with different stalk thicknesses. This combination affects the hydrodynamic properties of the ground surface, which in turn changes the velocity and distribution of run‐off. Current research on the influence of vegetation stalk thickness on water flow resistance is mostly focused on uniform vegetation. There have been few studies on the influence of non‐uniform vegetation on water flow resistance, and most have been qualitative in nature. In order to study the quantitative relationship between combinations of different stalk thicknesses and the water flow resistance of slope vegetation, a laboratory experiment was performed using a flume. The results show that when two different plant stalk thicknesses are staggered and combined, the diameters of the plants exhibit a power function relationship with the Darcy‐Weisbach resistance coefficient. When the diameter of the stem of one of the plants remains constant, at the same water depth, the coefficient of water flow resistance increases with the diameter of the stem of the other plant. Additionally, the coefficient of the vegetation flow resistance increases with increasing water depth. In the non‐submerged state, as the water depth increases, the rate at which the water flow resistance coefficient increases gradually declines, and as the diameter of any plant stem increases, the rate at which the water flow resistance coefficient increases also declines gradually. These findings provide a theoretical basis for the prevention and control of soil erosion and have important practical implications for maintaining water and soil resources.     

基于WEPPWIN软件的边坡优化

利用WEPPWIN软件模拟了不同坡度、坡形对水土流失的影响,介绍了WEPPWIN在坡度、坡形与水土流失关系研究中的实际应用,并得出相关结论,在此基础上提出了非对称边坡的设想,并指出其不足,以期提高我国公路路基边坡设计水平。     

上覆弹性板双层地基在移动荷载作用下的动力响应

 用Fourier变换及逆变换对移动荷载作用下路基路面系统的动力响应问题进行研究。考虑路基路面相互作用,假设一条形移动荷载作用在路面板的表面,地基以地下水位面为分界面分为双层,水位面以上为单相弹性土层,以下为饱和土层。考虑地基土层厚度有限,利用Lame对位移场的分解理论,引入势函数,并运用Fourier变换分别对弹性土层和饱和土层进行分析。在Fourier变换域内,结合边界条件,联立路面板、弹性土层和饱和土层的运动方程,得到土体竖向位移、应力和饱和土层内孔隙水压力的表达式;同时利用离散Fourier逆变换得到数值计算结果。计算结果表明,荷载速度、频率,饱和土层的渗透系数对地表竖向位移的影响很大;弹性土层厚度对竖向位移的影响依赖于荷载速度;弹性土层厚度以及弹性土层和饱和土层的相对刚度比对孔隙水压力有非常明显的影响。     

浅谈Novachip 超薄磨耗层技术在兰州机场高速公路的应用

Novachip超薄磨耗层作为一种新型的预防性养护技术,凭借优秀的路用性能和综合经济性,其主要用于交通量大、路用性能要求高的高等级公路、城市道路路面的预防性养护,具有改善路面平整度、减少水雾、抗滑性能、抗磨耗、降噪等特点,且施工简单、可靠、耐久性好。本文结合其工程实例,从施工工艺等方面介绍Novachip技术在路面养护中的应用情况,并对其与原路面的层间粘结强度进行了测试。     

开粒度与保水性沥青路面铺装材料表面蒸发冷却效果的比较

表面铺装是影响城市热岛现象的重要因素之一,而蒸发冷却是可以降低铺装表面温度的一种有效方法.研究可知现今采用的一般表面铺装材料不具有吸水性和保水性,而蒸发冷却效果仅仅在表面洒水后的短暂时间内产生作用.本文通过对蒸发冷却效果的定量分析,研制开发出了具有吸水性和保水性的表面铺装材料,具有长时间稳定的蒸发冷却效果,可在一定程度上缓解城市热岛现象.     

A mathematical approach to define threshold values of pavement characteristics

Transportation authorities managing road networks have to define threshold values of acceptance for pavement surface characteristics. This procedure is either based on relevant experience or drawn from a combination of subjective ranking and monitoring data. Rare are the references of an analytical procedure to define these threshold values with respect to the operational criteria of a road network: safety, comfort, environment and economy. Several road management agencies worldwide apply specific limit values for each pavement feature. Conversely, other authorities do not prescribe acceptance limits at all, allowing for high variability of local factors such as traffic and climatic conditions. In either case, the analytical approach to reliably define limit values is missing. In this study, a methodology to provide threshold values for pavement surface characteristics is presented. Three most important measurable characteristics of pavement conditions, skid resistance, roughness and rutting, are herein analysed. This analysis is carried out by introducing, respectively, suitable parameters, namely the sideway force coefficient, the International Roughness Index and the rutting depth. The objective is to outline a comprehensive methodology for determining threshold values for indicators that portray pavement condition. The proposed methodology attempts to define these limit values by spotting abrupt change in terms of safety or significant increase in negative effects to road users. Relative graphs are given correlating the aforesaid characteristics with safety and travel cost features. The overall analysis is based on the evidence of an ‘inflection’ point at each correlation curve, adequately interpreted to provide the threshold values in question.     

The effects of vegetation distribution pattern on overland flow

Soil erosion is a major environmental problem. Vegetation, on the other hand, plays an important role in controlling soil erosion. The goal of the study is to examine the effects of the distribution pattern of vegetation on water flow. The vegetation parameters involved included the direction of plant rows, plant stem diameter and row spacing. To study how vegetation affects the flow of water on slopes, flume simulation experiments were conducted using three different plant row directions, three different plant diameters and three row spacing. Experimental slope is fixed, slope ratio of 1.0%. The hydraulic characteristics of the slope under the three vegetation distribution patterns are explored. The results showed that the pattern of vegetation distribution significantly affected the resistance of vegetation to water flow and pattern on this slope. When the angle (θ) between plant row and water flow directions decreased, the plant diameter (d) increased, or the row spacing (a × a) decreased, the Darcy–Weisbach resistance coefficient (f) for water flow became larger. Simultaneously, the Reynolds and Froude numbers (Re and Fr) both became smaller. In experimental procedure condition, the change rate of f, Re and Fr were analysed by linear regression, the θ decreased every 10°, the average increase rate of f was 6.6%, the average decrease rate of Re and Fr were 2.0 and 3.0%. The d increased every 0.001 m, the average increase rate of f was 41.6%, the average decrease rate of Re and Fr were 11.2 and 12.2%. The a × a decreased every 0.01 m, the average increase rate of f was 45.2%, the average decrease rate of Re and Fr were 11.7 and 10.7%. The flow depth h increased every 0.01 m, the average increase rate of f and Re were 13.6 and 25.2%, and the average decrease rate of Fr was 10.4%. The experimental procedure results will be valuable for not only revealing the hydraulic characteristics of flow over vegetation land, but also the optimisation of the distribution of vegetation on a slope.