单侧边载作用下黏土中单桩负摩阻力特性模型试验研究

桩基础边载作用会在桩周产生负摩阻力,进而危及软土地区高桩码头、人工岛、路基等工程的安全。通过开展黏土中单侧堆载作用下单桩室内模型试验,测定桩身应变、桩顶沉降和水平位移,研究边载作用距离和桩型对桩身轴力及弯矩的影响,探讨桩身负摩阻力、桩顶沉降和水平位移在黏土固结过程中的时间效应。结果表明:边载作用距离对桩身最大轴力和最大弯矩有较大影响;翼板桩会增加桩身最大轴力和最大弯矩;负摩阻力和有效应力系数随时间增长且增速趋缓;增加边载作用距离和添加翼板都会提升桩身中性点位置,在这两组试验中均提升了8.33%。     

振冲碎石桩与CFG桩组合桩型复合地基试验研究

振冲碎石桩主要加固浅层地基,与桩间土构成复合地基,使地基承载力提高、变形减少,并可消除砂土层的液化;CFG桩布置在4根碎石桩的形心,桩端置于相对硬层,对复合地基的承载力和变形起控制作用。对某工程试验区振冲碎石桩与CFG桩组合桩型复合地基加固前后静力触探、动力触探和静载荷试验等进行研究,结果表明组合桩型复合地基中的碎石桩较大程度地提高了CFG桩的单桩承载力和地基承载力,桩距越小,加固效果越好。     

排桩整流技术内涵及应用

针对船闸下游引航道口门区横向流速超标问题,分析多种导流建筑物削弱口门区回流的机理,提出运用排桩调整水流流态的技术,并将排桩的概念进行延拓,涵盖以往多种导流建筑形式。结合物理模型试验,将排桩技术运用于大藤峡枢纽船闸下游引航道口门区水流条件改善中。成果表明:采用LD为1.0的排桩整流能降低口门区回流流速。     

复杂水流条件下抛石漂移距离的试验研究

抛石漂移是河道治理、护岸、潜丁坝、桥墩防冲等实际工程中经常遇到的问题,依托长江南京以下12.5 m深水航道二期工程口岸直水道整治工程,针对抛石漂移距离在试验室水槽内开展了一系列物理模型试验,对水深、流速、抛高、块石质量及块石形状的不规则等因素对抛石漂距的影响进行了研究;同时在考虑水流流速垂向分布的基础上,通过块石在动水中的受力分析推导出水上抛石漂移距离计算公式,利用模型试验结果拟合出公式中各系数的值,并将其计算结果与模型试验数据和现场观测数据进行比较,结果吻合较好,验证了公式的合理性。     

谐振直流环软开关电路的技术研究

阐述了应用于电压型逆变器的谐振直流环电路的工作原理,给出了其在MATLAB/Simulink中的仿真模型和仿真结果。通过仿真结果得出,谐振直流环电路可实现零电压开通,使开关损耗为零,但是电压u Cr谐振峰值很高,增加了对逆变器开关器件耐压的要求。     

Modeling the interactions between car and bicycle in heterogeneous traffic

In this paper, a new cellular automata model is proposed to simulate the car and bicycle heterogeneous traffic on urban road. To capture the complex interactions between these two types of vehicles, a novel occupancy rule is adopted in the proposed model to consider the variable lateral distances of mixed vehicular traffic. Based on massive simulations, microscopic fundamental diagrams under different bicycle densities are devised. With these, the bicycle's spilling behavior is then investigated and discussed. In order to reflect the interference of a bicycle on a car, the interference transformation from friction state to block state is modeled explicitly. Finally, different simulation results under different occupancy rules indicate that the constant and fixed occupancy rule adopted in the previous studies might lead to overestimation of car flux in the heterogeneous traffic flows with different bicycle densities. Copyright © 2013 John Wiley & Sons, Ltd.     

Large-scale evacuation network optimization: a bi-level control method with uncertain arterial demand

To improve the efficiency of large-scale evacuations, a network aggregation method and a bi-level optimization control method are proposed in this paper. The network aggregation method indicates the uncertain evacuation demand on the arterial sub-network and balances accuracy and efficiency by refining local road sub-networks. The bi-level optimization control method is developed to reconfigure the aggregated network from both supply and demand sides with contraflow and conflict elimination. The main purpose of this control method is to make the arterial sub-network to be served without congestion and interruption. Then, a corresponding bi-objective network flow model is presented in a static manner for an oversaturated network, and a Genetic Algorithm-based solution method is used to solve the evacuation problem. The numerical results from optimizing a city-scale evacuation network for a super typhoon justify the validity and usefulness of the network aggregation and optimization control methods.     

胶粉与SBS改性沥青混合料路用性能对比及质量控制

室内实验对胶粉与SBS改性沥青混合料路用性能进行对比分析,得出胶粉改性沥青混合料低温性能、水稳定性均优于普通SBS改性沥青混合料,高温性能与普通SBS改性沥青混合料相当。通过对改性沥青路面施工工艺分析,得出初压温度在施工中重要性。     

基于支持向量机的多传感器船舶火灾探测技术

针对船舶火灾探测误报率高的情况,为提高火灾探测系统的可靠性,提出一种基于支持向量机的多传感器火灾信息融合方法。经过仿真试验证明,通过多传感器探测数据的有效融合,可以大幅提高火灾探测系统的火灾识别率。     

紫外强化有效氯对船舶尾气同时脱硫脱硝试验

为提高有效氯溶液对船舶尾气同时脱硫、脱硝的性能,将紫外光(UV)辐照与有效氯溶液相结合,开展脱硫、脱硝试验。基于UV-鼓泡光催化反应器搭建模拟实验平台,进行UV辐照和无UV辐照环境下氧化溶液脱硫脱硝的对比试验和UV灯的功率、有效氯的浓度等因素对脱除率影响的试验。结果表明:在40℃的气液反应温度下,UV辐照能大幅度提高浓度为250 mg/L[CL2]的有效氯溶液对模拟烟气中NO、NOX和SO2的脱除能力;UV灯的功率从5W增加到16W,NO和NOX的脱除率近乎线性上升;将有效氯的浓度从250 mg/L[CL2]升高至1 500 mg/L[CL2],NO和NOX的脱除率缓慢上升;有效氯溶液对SO2的脱除率始终为100%。此外,对可能的反应机理进行了分析。