Microorganism and electric field combination reinforcing method for liquefiable foundation

Abstract

A microorganism and electric field combination reinforcing method for a liquefiable foundation comprises the following steps of a, drilling holes in the foundation to be reinforced, arranging grouting pipes a and b in rows and at intervals, and connecting the grouting pipes a with a cathode of a direct current power supply 4 into cathode grouting pipes 1 and connecting the grouting pipes b with an anode of the direct current power supply 4 into anode grouting pipes 2 through conducting wires 3; b, opening a first valve 8, and injecting a urease-producing microorganism solution 5 into the stratum through the cathode grouting pipes 1; c, when grouting begins, closing a switch 6 of the direct current power supply 4, forming a direct current electric field in a region between the cathode and anode grouting pipes, and after the action of the electric field finishes, closing the first valve 8; d, opening a second valve 8, injecting a cement solution 7 into the stratum through the cathode grouting pipes 1, closing the second valve 8, and standing for 8-12h; and e, exchanging the cathode and the anode which are connected with the grouting pipes a, repeating the steps b to d to carry out a new round of reinforcing on the foundation, pulling out all the grouting pipes after grouting is carried out on the place for required times, and pumping underground water to carry out sewage treatment.

Description

technical field [0001] The invention relates to a method for jointly reinforcing a liquefiable foundation with microorganisms and an electric field, and belongs to the technical field of foundation treatment. Background technique [0002] Sand or silt in a saturated state will liquefy when subjected to vibration, which will cause the foundation to lose its bearing capacity. The anti-liquefaction treatment and reinforcement of liquefiable foundations have always been an important technology in the field of foundation treatment. The reinforcement technology for liquefiable foundations, both There are traditional foundation reinforcement methods such as chemical solidification method, dynamic compaction method, and vibratory impact method, as well as microbial grouting reinforcement methods that have developed rapidly in recent years. [0003] The technical scheme of prior art one is as follows: [0004] The traditional method of strengthening the liquefiable foundation is to ...

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Problems solved by technology

[0008] The microbial grouting reinforcement method is an emerging method of strengthening liquefiable foundations. Under certain artificial environment and nutritional conditions, some non-toxic natural microorganisms (urease-producing bacteria, denitrifying bacteria, etc.) Calcium carbonate crystal with excellent cementation effect, which can well cement loose soil particles, can in-situ modify and solidify sandy soil and silt with low cohesion, and use microbial grouting reinforcement method to treat liquefiable foundation When using grouting equipment, the bacteria solution and cement solution are injected into the stratum to be reinforced in sequence, and then wait for the microorganisms to induce calcium carbonate crystals to complete the reinforcement of the foundation soil, and finally extract the solution containing high-concentration NH 4 Cl groundwater is used for sewage treatment, and the bearing capacity and anti-liquefaction performance of the foundation treated by the microbial grouting reinforcement method are significantly improved. Compared with the traditional reinforcement method, this method has the advantages of small construction disturbance, low site requirements, and no pollution. , no carbon emissions, no chemical residues, good biocompatibility with the reinforced soil, and good for environmental protection; but the disadvantage of the second prior art is: the existing microbial grouting reinforcement is mainly sandy soil, and there is a common phenomenon of reinforcement The problem of uneven solid strength and difficult control of the reinforcement range, the smaller the particle size of the soil, the more prominent the problem, with the continuous generation of calcium carbonate cement induced by microorganisms, the permeability of the reinforced soil will be significantly reduced, due to the microorganisms attached to the soil particles The spatial non-uniformity and the non-uniformity of the sedimentation reaction rate, there are significant differences in the strength and permeability of the near and far ends of the grout injection site, the larger the volume of microbial grouting soil, the more obvious this phenomenon, showing a significant Size effect, the inhomogeneity of the foundation after reinforcement makes the effect of improving the anti-liquefaction performance of the foundation limited, and also affects its large-scale promotion in engineering

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