侵入盾构隧道基岩地面钻孔地下爆破预处理及效果检验技术

Pretreatment of Bedrock Intruding into Shield Tunneling Scope by means of Blasting Hole Drilling from Ground Surface and Blasting Underground

基岩侵入隧道是盾构施工中经常遇到的问题。为解决盾构区间基岩突起并保证预处理效果达到盾构机顺利通过的要求,在前期物探及钻孔验证的基础上,结合现场实际情况,采用地表钻孔地下爆破的方法对不同的岩层厚度选择不同的炮孔间距及装药量。爆破后,采用高密度电法和钻孔取芯相结合的方法验证了基岩预处理效果。结果表明:基岩破碎效果良好,实测芯样最大长度为42 cm,97.4%的芯样长度均在30 cm以内,说明采用地面钻孔地下爆破处理基岩突起的方法是可行的,能够满足盾构顺利通过的要求;应用高密度电阻率法对破碎效果进行连续监测,提出了一些合理化建议,以期为今后类似城市地铁工程施工提供参考。

Bedrock intruding into the tunneling scope is a problem frequently encountered in shield tunn ject project, the bedrock intruding into the tunneling scope is pretreated by means of blasting hole eling. In the obdrilling from the ground surface and blasting underground. For bedrocks with different thicknesses, different blasting hole spacing and different charging quantities are adopted. After blasting, high-density electricity method and core drilling method are adopted to verify the blasting effect. The results show that the fragmentation of the bedrocks has achieved good effect ： the maximum length of the cores measured is 42 cm and the length of 97.4% of the cores is less than 30 cm. The practice demonstrates that the pretreatment of the bedrocks by means of blasting hole drilling from the ground surface and blasting underground is feasible and the requirement of successful shielding tunnel can be met.