跨线桥爆破塌落体触地震动土层动力响应实测与分析  

Field Tests and Analysis of Touchdown Vibration Soil Dynamic Responses of Overpass Blasted Collapse

作　　者：李慧鑫[1] 张巍[1] 丁龙琦 王道华[1] 孙可[1] 徐玉桂 戴晓玉 

机构地区：[1]南京大学地球科学与工程学院,江苏南京210046 [2]南京城建隧桥经营管理有限责任公司,江苏南京210037

出　　处：《南京工程学院学报（自然科学版）》2014年第1期14-18,共5页Journal of Nanjing Institute of Technology(Natural Science Edition)

基　　金：国家自然科学基金项目(40902076)

摘　　要：跨线桥爆破塌落体触地震动后应力波将沿土层传播,可能引起土层自身或土层中埋设的地下结构及设施产生较大变形,其不利作用不容忽视.依托南京城西干道某跨线桥爆破拆除工程,对塌落体触地处埋深14～20 m土层在桥体触地后的动力响应进行实测与分析.测试结果表明：本次触地震动的加速度幅值为0.15 ～0.42g,主频为2.61 ～6.69 Hz,触地震动持续时间约为1.85 s,最大竖向总应力增量为29.04kPa,最大超静孔隙水压力为22.64kPa.当可液化土层埋深较浅或防护不足时,局部土体存在液化风险,可采用废旧轮胎夹钢板缓冲震动以降低触地震动的影响.When the blasted collapse of overpass body touches the ground and vibrates, the stress wave propagates along the soil, which may cause the soil itself or the structures and facilities buried underground severely deformed. The adverse effects should be taken seriously. Taking the blasting demolition project of an overpass of Nanjing West Highway as a case study, this paper tests and analyzes the dynamic response of the soil layer of 14 to 20 min depth when the overpass body touches the ground. The tests show that the touchdown vibration acceleration amplitude is between 0. 15 to 0. 42g, the main vibration frequency between 2. 61 to 6. 69 Hz, the duration 1.85 s or so, the maximum vertical total stress increment 29.04 kPa, and the maximum excess pore water pressure 22. 64 kPa. When the depth of liquefiable soil buried is shallow or the protection is insufficient, the local soil is at the risk of liquefaction. Scrap tires and steel plate can be used as a kind of buffer protection to reduce the effects of touchdown vibration.

关 键 词：爆破拆除 跨线桥 触地震动 超孔隙水压力 

分 类 号：TU435[建筑科学—岩土工程]