破碎压实技术对城镇道路地下管道的振动影响与安全评价

摘要

破碎压实技术能将旧水泥混凝土路面破碎与压实后,直接作为新路面的基层或底基层使用,它在旧水泥混凝土路面改造中有越来越广泛的应用。然而,破碎机械对城镇道路地下管道会产生冲击振动,影响管道的安全。作者以MHB（多锤头破碎）机械为研究对象,分析冲击波的传递规律和面层结构的振动,并给出了振动引起的附加动应力和Steverding-Lchnigk动态脆性破裂准则的计算公式。以山东省泰安县城镇旧水泥混凝土路面破碎压实工程为例,对MHB冲击振动引起的附加动应力随深度的变化及破裂临界应力进行计算。计算结果表明：当路基中的振%Breaking and impacting technology is widely applied to treat the old Portland cement concrete（PCC） pavement due to the broken and impacted slabs directly being used as the base course or subbase course of the rebuilt pavement.However,the impaction vibration caused by breaking machine must influence the security of the buried pipelines under the urban road.Taken MHB（multiple head breaker） machine as an investigation object,the transmitting law of the impaction wave and vibration of the pavement structure were analyzed,and the calculation equations of the additional vibration stress and Steverding-Lchnigk criterion for brittle fracture were put forward.As an example of breaking and impacting engineering of an old PCC pavement in Taian city of Shandong province,the additional vibration stress varying with depth and critical fracture stress caused by MHB were calculated.The result indicated that the safe buried depth to a FRP sand-filling pipeline must be greated than 1.5m at a decaying period of 0.16s and 2.0m at a decaying period of 0.32s.