隧道开挖及爆破对地表高压铁塔影响的FLAC3D分析

以长湘高速公路李家冲隧道工程为背景,针对地表高压铁塔塔基受到隧道开挖及爆破影响的情况,运用FLAC^3D对铁塔4个塔基的沉降及质点振动速度进行了数值分析。并与现场实测数据进行对比分析,结果表明:(1)隧道开挖后铁塔塔基发生沉降,最大沉降量发生在测点3即1号塔基处,为3.55 mm。(2)施加爆破动载荷后,最大沉降量增量出现在1号塔基为2.23 mm ,其他塔基沉降量也有不同程度的增大。(3)塔基的质点振动速度幅值为4.2 cm/s,在允许的安全振速范围之内。质点振动速度与隧道开挖中线距离有关,距隧道开挖中线距离越近质点振速越大,反之则越小。分析结果与实际观测结果相吻合,并给出了避免爆破震动诱发地表铁塔塔基失稳塌陷的几条建议。

Analysis of Tunnel Excavation and Explosion Influence on High- Voltage Tower with FLAC3D

Taking the Lijiachong tunnel project in Changxiang express way as background, with reference to the influence of tunnel excavation and explosion on high-voltage tower foundations, this paper uses FLAC^3D software to numerically simulate settlement and particle velocity of four foundations of the iron tower and the conclusion in comparison with field data states as follows:(1)Foundation settlement of iron tower after tunnel excavation does exist and the greatest maximum settlement value is 3.55mm and in Foundation 1. (2)When exposed on dynamic explosive load, the maximum displacement increment exists in Foundation 1, whose value is 2.23 mm, and increment are also found in other foundations.(3)The amplitude of particle velocity of foundations is 4.2 cm/s, which is within the safety velocity range. Particle velocity is related to the middle line of excavation and the nearer the distance from the particle to the excavation middle-line, the greater the particle velocity value is and vice versa. The analytical results coincide with field test results and suggestions on how to avoid instability and subsidence of iron tower foundations after explosion are made.