下穿燃气管道爆破振动效应现场试验研究

Field experiment on blasting vibration effect of underpass gas pipelines

明晰下穿燃气管道爆破工程中的振动效应有助于更好地预测与控制爆破危害。通过下穿预埋燃气管道的现场爆破试验,采用动态测试手段,通过组合应变以及爆破应力波理论,分析爆破过程中爆破地震波的传播特点,研究管道及其上方地表土体的振动特点与应变特征,并计算得出管道允许应变和地表安全控制振速。结果表明:试验爆破地震波具有短时随机性,振动主频率主要集中在10~50 Hz范围内,主频较高,衰减较快,符合实际爆破工程中、远区爆破地震波传播规律,试验设计是合理的;管道中心截面为最危险截面,截面测点的峰值应变均以轴向峰值拉伸应变为主,截面背爆侧峰值拉应变大于迎爆侧;管道振速大于地表振速,管道允许应变值为366.4×10-6,管道正上方地表安全控制振速为8.5 cm/s。

Making clear the vibration effect of the gas pipeline due to blasting helps to better predict and control blasting hazards. Blasting test of buried gas pipelines was carried out by using dynamic monitoring measures,the propagation characteristics of blasting seismic waves during blasting were analyzed based on the blasting strain and stress wave theory. The vibration and strain characteristics of both the pipeline and the soil above the pipeline were studied,and the allowable strain of the pipeline and the surface safety control speed were calculated. The research indicates that the experimental blasting seismic wave has short-term randomness,and that the main frequency of vibration mainly ranges from 10 Hz to 50 Hz and attenuates fast,which conforms to the propagation law of the blasting seismic wave in the far area of actual blasting engineering and hence shows the reasonability of the test design. The cross section of the pipe center is most dangerous,in which the peak strain of the measurement point is mainly the axial peak tensile strain. The peak tensile strain on the back side of the section is larger than that on the explosion side,and the vibration velocity of the pipeline is greater than the surface vibration velocity. The allowable strain value of the pipeline is 366.4× 10-6 and the surface safety control velocity above the pipeline is 8.5 cm/s.