Reinforcement Treatment On Unloading(Loose) Rock Mass Of Jinping First-Stage Hydropower Station

Jinping first-stage hydropower station in a high mountain and deep gorge area,geological environment is complex, unloading strong, rock mass quality is poor, reinforcement the key to influence the slope stability.Support method of slope include anchor cable and anchor,need much drilling,boring become the second important work after excavation.As f5,f8 and other factors,frequently Sticking, swap block, collapse, air leakage and other accidents when drilling pass through Broken rock,project can not proceed smoothly. Grounting cement slurry(mortar), however, unloading rock of slope even get loose, slurry miss along the crack, Although the use of waiting for solidification,limiting traffic and other remedies, however, no effect. Grounting in some anchor holes for months, but there is no effect of consolidation.For the grounting problem of the left bank slope rock, so in this paper,the main research object is the grounting reinforcement treatment on unloading(loose) rock mass of the left bank slope.The detail content and acquired results are as following:1)Based on drilling,adit investigation and excavation, research rock mass structural characteristics of the slope section that problems highligh,including:from the opening line to 1960m elevation tram platform,1960m to 1885m dam crest,dam crest elevation to 1730m pedestal elevation, analysis structural characteristics of the rock mass, according to classification of the size of various types of structural surface characteristics, elaborate control significance of the geological structure to grouting.2)This paper analyzes the reinforcement treatments used currently and the failure of the problems, summarize the shortcomings of common slurry, propose three kinds of grouting materials of new time-varying cement slurry: additive 1#,2#,3#. Analyzes"penetration"reaction of the time-varying slurry, research slurry diffusion theory model in fractures, and consider the main factors affecting slurry,apply grouting spread of test equipment which is independent study,simulate spread curves in a certain slurry pressure and water pressure, crack, different angle of the joint, study the spread mode of the slurry, suggesting the trend.3)Design of the "three factor, three level" orthogonal test program, use integrated balance method to reach two most factors that affect slurry, get the best experimental program.the best pilot program for requirements. Specially study additive 2#,3# on the impact of the nature of the slurry.4)Tested current slurry(λ= 0.45) and cement mortar (w: c: sand: superplasticizer = 0.45:1:1:0.004) of mobility, pumping time, setting time, strength and other parameters, and with comparison of time-varying slurry,analysis the characteristics of slurry from the point of view on time-varying nature.5)April 2008, November and December, tested new time-varying slurry on the EL1825m and EL1730m elevation test area of left bank,recorded Grouting volume,Flow and other parameters,compared with the use of common slurry from the volume of cement and time-consuming.