The attempt of cross-hole resistivity CT technique to check the effect of ground pre-grouting in the shaft
When the shaft excavation meets aquifers or soft broken formations,ground pre-grouting is a common water blocking and strengthening technology,but there is no reliable means to check and e-valuate the grouting effect.The rapid development of geophysical exploration technology brings new hope for the inspection of ground pre-grouting effect.However,up to now,there are no reports of checking and evaluating the effect of ground pre-grouting of shaft by means of geophysical exploration.Based on the introduction of geophysical exploration technology,this paper analyzed the reason why the conventional geophysical exploration technology could not be applied in the inspection of the ground pre-grouting effect of the deep shaft,and the principle,method and instrument of the ultra-high density cross-hole resistivity CT technology was expounded,and tried to apply it in the ground pre-grouting of the new shaft in the Xianglu Mountain water diversion tunnel of the Yunnan Dianzhong Diversion Project.The results show that ultra-high density cross-hole resistivity CT tech-nology has the characteristics of high resolution,low ambiguity and automatically rapid data collection.Compared with the ground geophysical exploration method,the test through drilling into the grouting stratum can more accurately reflect the change of the formation physical property param-eters,and the qualitative inspection and evaluation of the deep ground pre-grouting effect in a large scale is feasible,and more studies and attempts should be made.
water diversion tunnelground pre-grouting in the shaftinspection of grouting resultgeo-physical exploration technologycross-hole resistivity CT
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