Water -free pebble back to fill the strata shield wall structure and grouting material

Abstract

The invention discloses an anhydrous pebble backfill formation shield wall post-grouting material which comprises, by weight, 10-16% of fly ash, 2-3.2% of lime, 0.5-4.5% of bentonite, 54-57% of stone chips and the balance of water added to 100%. Characteristics of an anhydrous pebble backfill formation are combined, specific raw materials and mixing proportion are adopted, needs on workability and fluidity of formation grouting liquid are met, cost is lowered greatly, loss of the grouting liquid is prevented, initial setting time of the grouting liquid is reduced, and ground surface settlement and duct piece dislocation are controlled effectively. The stone chips are adopted to replace river sand, so that local materials can be used and are convenient, quick and cheap in price, and economic cost is saved; lime is adopted to replace cement, so that setting time is shorter, and cost is lower.

Description

technical field [0001] The invention relates to a grouting material, in particular to a grouting material for backfilling a formation shield wall with anhydrous pebbles. Background technique [0002] Anhydrous sand and pebble backfill formation is a typical mechanically unstable formation, there is almost no cohesion between particles, the point-to-point force transmission path is simple, and the formation is sensitive. When the cutter head rotates and cuts, the formation is easy to destroy the original relative stability. or equilibrium state to cause collapse, causing large formation loss and surrounding rock disturbance, and the ground subsidence reaction rate is fast. Therefore, the shield tunneling method in this formation has higher requirements for synchronous grouting. At present, the synchronous grouting slurry usually used in the shield tunneling construction of anhydrous sandy pebble formation is mainly "water + cement + sand + bentonite + fly ash" after a certai...

AI Technical Summary

Problems solved by technology

This kind of grout has the following disadvantages: (1) Due to the large voids in the sand and pebble formation, the grout spreads quickly, and the grouting pressure often does not reach the set value (that is, the grouting pressure does not increase, and the grout runs too much), resulting in waste of grout Serious; (2) The synchronous grouting grout has a long initial setting time and low early strength, which is easy to cause segment misalignment and other phenomena. uneven dislocation); (3) the surface subsidence is too large; (4) the amount of cement, river sand, etc. is too large, which is uneconomical