Microbial grouting test device and test method for uniformly solidifying silty soil

Abstract

The invention discloses a microbial grouting test device and a test method for uniformly solidifying silty soil. The device comprises a cementing liquid supply device, a grouting device and a negative pressure liquid extraction device, wherein the grouting device consists of a grouting barrel body consisting of an inner barrel and an outer barrel; an interlayer cavity is formed between the inner barrel wall and the outer barrel wall; a grouting hole is formed in the inner barrel wall; the top of the barrel body is communicated with the cementing liquid supply device through a liquid supply pipe; the bottom of the barrel body is communicated with the negative pressure liquid extraction device through a liquid discharging pipe; cementing liquid vertically flows into an inner cavity of the inner barrel from the top of the inner barrel and transversely flows into the inner cavity of the inner barrel through the interlayer cavity and the grouting hole; a silty soil layer for grouting is arranged above the inner cavity of the inner barrel, and a coarse sand filtering layer is arranged below the inner cavity of the inner barrel. The test device disclosed by the invention can realize automatic supplying of the cementing liquid, so that a large number of sediments in a liquid supply measuring barrel can be reduced; meanwhile, migration of the cementing liquid in a whole soil sample is realized, so that local blockage of calcium carbonate is prevented; the uniformity of distribution of the calcium carbonate in the whole test sample is improved; the solidifying effect is enhanced.

Description

technical field [0001] The invention relates to an indoor model test device and a test method, in particular to a microbial grouting test device and a test method for uniformly solidified silt. Background technique [0002] Microbe-induced calcium carbonate deposition (MICP) is a green and environmentally friendly new solidification technology. At present, it is widely used in the solidification of coarse-grained soil such as sandy soil and gravel soil with good permeability. The indoor test treatment methods generally include grouting type and immersion type. However, due to the limitation of pore size and bacteria size, silt has low permeability, and it is difficult for microbial cement to migrate in the pores. It often needs to be reinforced by pressure grouting or pre-mixed bacteria. The pressure method will disturb the soil, and the strength of the treated silt has obvious inhomogeneity, which is often reflected in the high calcium carbonate content in the upper part o...

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Problems solved by technology

However, due to the limitation of pore size and bacteria size, silt has low permeability, and it is difficult for microbial cement to migrate in the pores. It often needs to be reinforced by pressure grouting or pre-mixed bacteria. The pressure method will disturb the soil, and the strength of the treated silt has obvious inhomogeneity, which is often reflected in the high calcium carbonate content in the upper part of the silt column, bacteria gather in the upper part, and calcium carbonate is easy to form in the upper part of the soil column. Partial blockage affects the subsequent migration of the cementing fluid, making the lower part of the silt with a low calcium carbonate content, which is in the form of loose particles, and the curing effect is poor

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