Construction method for lowering construction compactness requirement of high-liquid-limit soil subgrade construction by doping sand

Abstract

The invention discloses a construction method for lowering the construction compactness requirement of a high-liquid-limit soil subgrade construction by doping sand. The method comprises the following steps of: A, doping sand in high-liquid-limit soil in a subgrade; evenly stirring by using a rotary tiller, wherein the sand-doping amount is 15-25 percent; B, covering; and C, rolling by adopting a road roller, wherein the first static rolling speed is 1.5-1.7km / h, and the later rolling speed is 2.0-2.5km / h. Compared with raw soil, sand-doped modified soil which is adopted in the invention scheme increases the maximum dry density and decreases the optimal water ratio; due to the existence of rough particles in the rolling process, water and air in the soil can be smoothly discharged so as to reach the requirement for higher subgrade strength; after sand is doped, the strength and the stability of the soil body are enhanced, and the shrinking stress of the soil is lessened to prevent the subgrade from cracking. The scheme of the invention greatly decreases the construction cost without causing dust-rising phenomenon or environmental pollution in the construction process.

Description

technical field [0001] The invention relates to a construction method of a high liquid limit soil subgrade project, in particular to a construction method for reducing the compaction requirement of the high liquid limit soil subgrade project by mixing sand. Background technique [0002] According to the Highway Geotechnical Test Regulations (JTG E40-2007), fine-grained soils with a liquid limit greater than or equal to 50% are collectively referred to as high liquid limit soils. Typical characteristics of high liquid limit soils are high natural moisture content (much higher than optimal moisture content), high liquid limit, large plasticity index, and large particle content variation. In the test soil, the highest liquid limit exceeds 80%, the plasticity index exceeds 40; the proportion of fine particles is as high as 85.7%. A moisture content much greater than the optimal moisture content indicates a higher saturation of the soil layer; a high liquid limit and a large pla...

AI Technical Summary

Problems solved by technology

At present, our company has passed experiments and found that among the improvement schemes that can meet the compaction degree of 93%, it is feasible to reduce the compaction requirements of high liquid limit soil subgrade engineering by using quicklime stewed material, but the cost is relatively high through estimation. And the stew mixed with quicklime will splash a lot of dust during the mixing process, which will pollute the environment to a certain extent.

Its defect is: promptly uneconomical, not environmental protection again

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