浅谈沥青混凝土路面裂缝的综合防治

路面裂缝是沥青混凝土道路的主要病害之一,故应针对裂缝产生的类型及原因,在路面结构设计中和道路材料应用上,以及在道路施工、养护方面采取综合防治措施,从而防止、延缓沥青混凝土路面裂缝的产生,延长路面的使用寿命。     

复合式路面反射裂缝防治技术的探讨

水泥混凝土路面加铺沥青罩面层,可有效地改善路面的路用性能,提高道路的服务水平,延长路面的使用寿命,但反射裂缝的出现会严重削弱复合式路面的这些优势,故对如何防治的问题需进行深入的研究和探讨。     

浅谈道路裂缝的危害及防治措施

结合工程实践,从分析道路的横向裂缝和纵向裂缝的成因及危害入手,阐述了道路裂缝的防治措施,为道路施工和养护提供参考意见和建议。     

表面裂纹Ⅰ型应力强度因子间的互相作用及影响规律

基于有限元软件France-3D对含有多个裂纹的平板进行应力强度因子计算．通过定义基础裂纹、干扰裂纹以及干扰参数r,α,β和2b等,给出了随干扰参数r,α,β改变,干扰裂纹对基础裂纹应力强度因子影响的λ-4,λ-α理曲线,并分析其规律,其结果可为工程应用参考．     

中速船用柴油机喷油泵顶杆机构导筒裂纹分析

利用虚拟样机技术建立某型中速柴油机喷油泵顶杆机构的虚拟样机模型,对模型进行仿真分析,得到喷油泵顶杆机构导筒动态载荷.对喷油泵顶杆机构的导筒进行有限元建模,根据侧推力选取危险工况后进行结构强度分析,并根据强度分析结果进行疲劳分析.通过分析得到以下结论:导筒与滚轮导筒间隙增大造成导筒侧向载荷增大,最终导致导筒疲劳断裂.     

Depth estimation of surface cracks based on the measurement of crack opening deformation and numerical–experimental iteration

We propose a new method to estimate the depth of a surface crack based on the measurement of crack opening deformation (COD) by using strain gauges. Through finite-element (FE) analysis of several surface cracks with different crack depth, it was found that the distribution of crack depth along the crack line can be approximated by multiplying a certain proportional α to the distribution of COD per unit nominal strain (normalized COD). The strain gauges are cemented just on the crack line and at a reference position, and the normalized CODs are measured under the impact load excited by hammer punching. The surface crack depth is estimated from the normalized COD measurements by a numerical–experimental iteration method based on FE analysis. The estimated distribution of the surface crack depth along the crack line shows good agreement with the shape of a real crack depth.     

从“缩缝”的切割谈水泥混凝土路面早期断裂的防止与处理

根据近年施工经验 ,着重叙述在施工过程如何控制和防治混凝土路面早期断裂     

高速列车制动盘裂纹现状调查分析

对我国高速列车“中华之星”及“先锋号”上用的制动盘裂纹现状进行全面调查。分析了制动盘裂纹剖面的宏观形貌特征,并对制动盘裂纹萌生和扩展机理进行探讨。发现裂纹剖面宏观形貌特征与制动盘疲劳裂纹扩展规律之间存在一定的关联,为制动盘寿命评估提供了新的思路。     

Real-time crash prediction for expressway weaving segments

Weaving segments are potential recurrent bottlenecks which affect the efficiency and safety of expressways during peak hours. Meanwhile, they are one of the most complicated segments, since on- and off-ramp traffic merges, diverges and weaves in the limited space. One effective way to improve the safety of weaving segments is to study crash likelihood using real-time crash data with the objective of, identifying hazardous conditions and reducing the risk of crashes by Intelligent Transportation Systems (ITS) traffic control. This study presents a multilevel Bayesian logistic regression model for crashes at expressway weaving segments using crash, geometric, Microwave Vehicle Detection System (MVDS) and weather data. The results show that the mainline speed at the beginning of the weaving segments, the speed difference between the beginning and the end of weaving segment, logarithm of volume have significant impacts on the crash risk of the following 5–10 min for weaving segments. The configuration is also an important factor. Weaving segment, in which there is no need for on- or off-ramp traffic to change lane, is with high crash risk because it has more traffic interactions and higher speed differences between weaving and non-weaving traffic. Meanwhile, maximum length, which measures the distance at which weaving turbulence no longer has impact, is found to be positively related to the crash risk at the 95% confidence interval. In addition to traffic and geometric factors, wet pavement surface condition significantly increases the crash ratio by 77%. The proposed model along with ITS, e.g., ramp metering, Dynamic Message Sign (DMS), and high friction surface treatment can be used to enhance the safety of weaving segments in real-time.     

高等级公路沥青路面裂缝类损坏危害及防治措施

分析了高等级公路沥青路面裂缝类损坏产生的原因,并提出了相应的防治措施。