深厚淤泥中插入竹竿减震沟减振效果试验

Test of Damping Effect of Damping Ditch with Inserted Bamboo on Condition of Thick Silt Base

减震沟是减小振动效应的重要措施,但在地表下淤泥层深厚以及软土地层中减震沟开挖深度受到地质条件的影响,减震沟无法开挖到有效降振深度,因此提出以多排空心竹竿竖向插入减震沟底的方法进行减振。在漳州东立交桥拆除爆破工程中进行现场试验,通过对实测数据的分析表明:塌落振动异于爆破振动,有频率低、振动大的特点;对于深厚淤泥层及软土地质,开挖减震沟时较易塌方;减震沟沟壁软弱,侧壁存在应力放大效应,拆除物外围防护与减震沟应保持适当距离;采用减震沟中插入竹竿的方法进行减震是可行的,爆源近区最大减震率可达50%以上。

The damping ditch is an important measure to reduce the blasting vibration effect. However,the depth of the damping ditch couldn＇t reach the effective depth of vibration reduction when the stratum environment was thick silt base or weak soil. So the method of the damping ditch with vertical inserted multi-row hollow bamboo was used to reduce blasting vibration. The field test was carried out in the explosive demolition of Zhangzhou East overpass. Through the analysis of the measured data,the results show that, the collapse vibration was different from blasting vibration, which has the characteristics of low frequency and high vibration. It is easy to collapse when excavation the damping ditch in the thick silt base or weak soil. The wall of the damping ditch was weak, the side wall had stress amplification effect,the external protection of the building and the damping ditch should be kept in a proper dis- tance. By the method of the damping ditch with bamboo to reduce vibration is feasible, the maximum decreasing ant- plitude ratio in the area near blasting source is more than 50%.