Experimental Study On Expansion Tuff Stability Control

Yunnan LanCang lead ore mining area fault fold development, stratum contains a lot of swelling tuff, under the influence of a large amount of groundwater, Complex geological conditions and engineering disturbed, mining roadway damaged badly, supporting difficulty, and Invalid repair many times, it is the typical representatives of the victims by the soft rock engineering problems.Tuff is a kind of with special engineering properties of soft rock, Because contain clay minerals, water swelling, Softening disintegration easily. For the expansion of rock, often use clay stabilizer prevent clay hydration expansion, at the same time using anchoring and shotcreting to improve the stability of surrounding rock. But the general clay are small molecular weight modifier, used in oil additives, rarely studied mining of swelling rock seepage water plugging, and small molecular weight of the clay modifier for the expansion of the macropore rock filling effect is poorer, and anchor contact with the surrounding rock unstable, often do not have anchoring effect. Based on this, This paper creatively puts forward using high molecular weight cationic polyacrylamide, abbreviation CPAM, For LanCang lead dilatability tuff modified, meanwhile, using the CPAM+ cement Composite net pulp grouting reinforcement, improve the overall stability of surrounding rock. Through theoretical analysis and experimental verification, made the following main results:1. By free expansion experiments with tuff grading disintegration matter was found, CPAM modified liquid than other clay modifier, has the more stable, long-lasting, excellent suppression of swelling properties. CPAM tuff modified substantially liquid swelling disintegrants, swelling suppression optimal concentration of 0.08%.2. Different concentrations, CPAM solution viscosity at different temperatures were me-asured analysis, the approximate logarithmic relationship between CPAM slurry visc-osity and density, greatly affected by the concentration, little affected by temperature conclusion. CPAM slurry viscosity and relationship between the temperature and the concentration and the numerical fitting.3. Point load test by composite slurry test block, draw CPAM solution concentration is 0.06% water-cement ratio of 0.45 composite slurry highest compressive strength test block, relatively non-modifier test block of cement paste to mention a strong 33.7%.4. Simulation engineering, simulation grouting homemade instrument, and tuff samples were simulated chemical grouting. Using macro photography, scanning electron micr-oscopy and spectroscopy methods combining diffusion effect after grouting test bloc-ks were experimental analysis showed that the modified CPAM good to inject liquid slurry diffusion more fully, and for this experiment materials, without appropriate co-nfining pressure grouting pressure is simulated 0.6MPa. Meanwhile, after grouting point load test block experimental results show that the CPAM solution did not cause damage to the tuff strength, but there is some improvement..5. For Lancang Lead instability problems raised roadway targeted stability control program, focused on the performance of "water control" and "reinforcement" two means, and improved conventional grouting pipe.