Preparation method of low-shear-strength grouting material for shield excavation gap

Abstract

The invention discloses a preparation method of a low-shear-strength grouting material for a shield excavation gap. The preparation method comprises the following steps: selecting a grouting material; preliminarily designing multiple groups of grouting materials with different water cement ratios and multiple groups of grouting materials with different swelling-water ratios; manufacturing a plurality of groups of grouting material test pieces; testing the shear strength of each group of test pieces to obtain the optimal water-cement ratio and the optimal swelling-water ratio of the grouting material; adding bentonite and water into a stirrer according to the optimal swelling-water ratio, conducting stirring, fully and uniformly conducting mixing, conducting standing, and fully conducting swelling; measuring water glass with required baume degree, adding the water glass into expanded bentonite slurry, and uniformly conducting stirring; and adding cement powder, and continuously conducting stirring uniformly to finish the preparation. The filling problem of the excavation gap in shield construction is studied, and the problem that a shield body is locked by a conventional shield body grouting material can be solved; and a novel filling material configuration method is adopted, the pumping requirement in grouting equipment is met, and meanwhile high shear strength is achieved.

Description

technical field [0001] The invention belongs to the technical field of shield tunnel construction, and in particular relates to shield tunnel grouting technology, in particular to a configuration method for low shear strength grouting materials in shield tunnel excavation gaps. Background technique [0002] In addition to the grouting material, the grouting effect is also related to the grouting parameters such as the grouting pressure and grouting time in the shield construction process. In the existing research, experts and scholars have studied the grouting diffusion radius, Factors such as the strength of the stone body after grouting were studied, so as to obtain the relationship between the grouting parameters and the filling effect. [0003] Yang Ping et al. used the indoor test method to conduct grouting experiments on sand and pebble formations, and concluded that the grouting pressure has the most significant impact on the slurry diffusion radius, followed by the p...

AI Technical Summary

Problems solved by technology

(1) The initial strength of the filling material is relatively low, and it cannot interact with the soil outside the shield shell in time, or the setting of the initial setting time is unreasonable and other factors cannot achieve real filling;

(2) The proportion of filling materials is unreasonable, which may cause the filling material to have too good fluidity, flow to the cutter head and consolidate, causing the cutter head to twist greatly, or the workability is poor, and the filling material segregates, resulting in filling For material loss, the strength and impermeability of the filling material should be improved for the fast approaching portal and communication channel;

(3) For different formations, the effect of filling materials may be different

If the filling effect is controlled by the filling amount, it may not be able to form an effective support for the soil around the shield shell due to reasons such as low strength of the filling material or high self-shrinkage

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