窄路肩条件下保护层厚度对4级波形梁护栏防护性能的影响规律

Influence of Thickness of Protective Layer on Performance of Class 4 W-beam Barrier under Narrow Shoulder Condition

为解决公路波形梁护栏设置在土路肩时,在窄路肩条件下立柱保护层厚度不足从而导致护栏无法设置的问题,依据现有公路横断面状况及规范,选取3种不同宽度土路肩条件和一种极限条件下的护栏立柱保护层厚度,按照1∶1比例分别建立了4种四(SB)级波形梁护栏的仿真模型。采用计算机仿真方法对4种工况的四(SB)级波形梁护栏防护性能进行了碰撞仿真计算。以最不利车型分析了不同保护层厚度条件下车辆碰撞护栏的最大横向动态变形值、最大横向动态位移外延值、最大动态外倾值、最大动态外倾当量值、车辆乘员碰撞速度和碰撞后加速度等防护性能参数。通过对比各种工况条件下的护栏防护性能参数指标,得到了不同保护层厚度条件对护栏各项防护性能指标的影响规律。采用实车足尺碰撞试验方法,以小型客车、中型客车、大型货车3种车型验证了在12 cm保护层厚度条件下护栏的安全防护性能,并以中型客车验证了在0 cm保护层厚度条件下的护栏安全防护性能。试验结果验证了窄路肩条件下四(SB)级波形梁护栏的可靠性,护栏防护性能满足评价标准要求,四(SB)级护栏可应用在土路肩宽度为50 cm的路段,极限条件下四(SB)级波形梁护栏可应用于土路肩宽度为38 cm的路段。

To solve the problem of insufficient post protective layer thickness under narrow shoulder condition when highway W-beam barrier is set on soil shoulder,which leads to the inability to set barrier,based on the current cross-sectional conditions of highways and specifications,selecting the protective layer thicknesses of barrier posts under 3 width soil shoulder conditions and a limit condition,4 simulation models of Class 4(SB)W-beam barrier are established in 1∶1 ratio.The collision simulation calculation of the protective performance of Class 4(SB)W-beam barrier under 4 conditions is performed by computer simulation method.With the most unfavorable vehicle type,the maximum lateral dynamic deformation,the maximum lateral dynamic displacement epitaxial value,the maximum dynamic camber value and the maximum dynamic camber equivalent value of the vehicle-barrier collision,the collision speed of vehicle occupants and the acceleration after collision and other protective performance parameters under different protective layer thickness conditions are analyzed.By comparing the protective performance parameters of barrier under various working conditions,the influences of different protective layer thickness conditions on the protective performance indicators of barrier are obtained.By using the full-scale test method on real vehicle,the safety protection performances of barriers under 12 cm protective layer thickness are verified using small bus,medium bus and large truck.The safety protection performance of barriers under the condition of 0 cm protective layer thickness is also verified using medium bus.The test result verified the reliability of Class 4(SB)W-beam barrier under narrow shoulder condition,the barrier protection performance meets the evaluation standard,the Class 4(SB)W-beam barrier can be applied to the sections with soil shoulder width of 50 cm,and can be applied to the sections with soil shoulder width of 38 cm under extreme condition.