复杂条件岩质深基坑炸药爆破联合静态破碎方案设计与应用

Design and Application of Explosive Blasting Combined with Static Crushing Scheme for Rock Deep Foundation Pit under Complex Conditions

在保证基坑安全和周边环境正常使用的前提下,为了将炸药爆破范围最大化,使石方开挖最快速和最经济,先对基坑周边环境条件进行详细调查,对拟保护的建(构)筑物及管线以及侧壁支护结构的安全振速进行合理确定,找出对炸药爆破最敏感的重点保护对象。通过现场炸药爆破试验,分析出控制爆破范围与重点保护对象的安全距离,对保护对象有安全影响的石方采用静态破碎开挖方法。试验结果表明:采用城镇浅孔逐孔松动爆破技术,控制单次起爆药量,微差分段起爆,距离最敏感的重点保护对象侧壁支护结构3 m以上时,爆破振速能够控制在10 cm/s以内,未造成破坏性影响,靠近基坑侧壁的3 m范围内采用静态膨胀结合液动锤破碎开挖,基坑变形监测表明安全稳定。该方案使基坑石方开挖工期大大加快,造价得以控制,对类似工程具有参考价值。

On the premise of ensuring the safety of the foundation pit and the normal use of the surrounding environment,in order to maximize the scope of explosive blasting and make the stone excavation the fastest and most economical,firstly conduct a detailed investigation of the surrounding environmental conditions of the foundation pit,reasonably determine the safe vibration velocity of the buildings(structures)and pipelines to be protected and the side wall support structure,and find out the key protected objects that are most sensitive to explosive blasting.Through the on-site explosive blasting test,the safe distance between the controlled blasting range and the key protected objects is analyzed,and the static crushing excavation method is adopted for the stonework that has a safety impact on the protected objects.The test results show that when the distance from the most sensitive side wall support structure is more than 3 m,the blasting vibration speed can be controlled within 10 cm/s without damaging effects when using the town shallow hole hole by hole loosening blasting technology to control the single detonating charge and millisecond staged blasting.The static expansion and hydraulic hammer crushing excavation are used within 3 m near the side wall of the foundation pit.The deformation monitoring of the foundation pit shows that it is safe and stable.This scheme greatly accelerates the construction period of rock excavation of foundation pit and controls the cost,which has reference value for similar projects.