Method for strengthening construction of karst cave grouting
Date:2014-08-11 Views:902Times
1, use the grouting pump grouting, grouting pressure should not be too large, controlled in the range of 0.3 ~ 0.6MPa, the specific pressure value determined by field test. Speed is 15 ~ 20L/min, its purpose is to make the slurry penetration to the filler within (including filled sand or gravel), and then the consolidation, permeability of minimum diameter is 3.0m, in order to ensure the mutual connection of consolidation body. When Grouting grouting pipe must be inserted into the bottom edge of the filler, and then grouting and slow lifting, the lifting pipe speed not too fast, determined according to the grouting speed, should make the penetration radius controlled in allowable range. Slurry slurry selection, with 32.5 grade cement, clay powder mixture, mixing ratio (weight ratio): cement: mud powder =3:7, water cement ratio 1:0.5. Need double grout, content of water glass is determined according to the field test.
2, filling grouting, grouting pipe with D48 pipe, the pipe body cave range open plaza of grout hole, hole sealing grouting. When grouting, grouting speed determined by analysis and end time, according to the penetration radius, consolidation volume to calculate the amount of pressure into the formula for the Q= R2H beta, PI Mu alpha lambda (1- gamma). Type, R as the penetration radius; H cavern height; Mu filled porosity; alpha is super filling coefficient; lambda for regional experience coefficient; gamma, beta for filling rate and filling coefficient. These parameters and coefficients can be determined according to the field test.
3, in order to prevent the loss caused by filling slurry is too far the other grouting hole, the use of intermittent grouting method, make the slurry and sand first injection (or gravel) reached a preliminary cemented after grouting, grouting repeatedly, until the required minimum of grouting amount and pressure control value.
4, the infusion of a hole, continue to rest after the grouting hole, grouting pressure has to be increased, the last hole sealing. The injection sequence by site on their own hands.
5, each grouting hole grouting per meter according to the amount of 2 cubic meters of preliminary consideration. The practical grouting parameters is determined according to the field experiment. Liquidity for karst water, should be in the slurry adding accelerator or cement - water glass double liquid.
6 construction technology, grouting method: insert the steel casing in drilling in the deep hole grouting, the technological process is as follows:
Hole lofting, hole drilling, drilling drilling emplacement depth to the design to the cement slurry preparation, grouting pipe, high pressure grouting, grouting liquid, moving back to the next hole.
The key points in implementation of 7, grouting reinforcement
The layout of grouting holes
Grouting hole in accordance with the spacing of 2.5m.
Single hole grouting over standard
Asked a few times, repeated grouting; grouting are normal for each section, final grouting pressure reaches the final pressure, grouting amount reaches the design of grouting quantity 80%, or has not yet reached the final pressure, but the grouting amount has reached the design of grouting quantity, to the end of the hole grouting.
8, if encounter greater Cave (no filler), poured into crushed stone requirements such as a large number of filler, must drill a large hole (diameter less than 30cm) into the steel tube and steel tube is fixed, detritus hopper, gravel particle size of not more than 1cm, the vibration tube feeding, to prevent blockage.
