Additive for reducing inhibition of seawater on swelling performance of bentonite

Abstract

The invention discloses an additive for reducing inhibition of seawater on swelling property of bentonite. The additive comprises, by weight, 25-30% of zeolite powder, 30-40% of an ion exchange resinand 35-45% of sodium carbonate. The invention aims to prepare a slurry meeting engineering requirements by utilizing seawater. The method can solve the problem of bentonite mud performance degradationcaused by seawater ions, especially solve the problem of great reduction of bentonite bulking performance in seawater mud, and prepare seawater mud with performance parameters similar to those of fresh water mud, such as viscosity, colloid rate, mud solid particle average particle size D50 and the like. The additive can solve the problem of adaptability of bentonite in seawater, fully utilize seawater resources, save fresh water resources, and has good economic benefits, environmental protection benefits and social benefits.

Description

technical field [0001] The invention relates to the field of engineering mud, in particular to an additive for reducing the inhibition of seawater on the swelling performance of bentonite. Background technique [0002] With the gradual maturity of shield construction technology in our country, the conditions of shield tunneling projects have become more and more severe, such as large-section, high-permeability stratum construction, etc., and more and more shield constructions have exceeded the limit of surface settlement and collapsed. Such quality accidents are largely caused by ignorance of synchronous grouting technology for shield construction and incorrect selection of grouting materials. In the process of shield tunneling, mud is the key material to maintain the stability of the excavation surface, and the solid particle gradation of the mud is the core factor affecting the stability of the excavation surface, followed by parameters such as specific gravity, viscosity,...

AI Technical Summary

Problems solved by technology

In the process of shield tunneling, mud is the key material to maintain the stability of the excavation surface, and the solid particle gradation of the mud is the core factor affecting the stability of the excavation surface, followed by parameters such as specific gravity, viscosity, and colloidal rate. If the particle size of bentonite in the mud is small, it may directly pass through the pores of the formation, resulting in a large amount of mud filtration, and it is difficult to maintain the stability of the excavation surface

[0003] Seawater has high salinity and rich content of various ions, which will have a great impact on various properties of mud, such as mud viscosity, colloid rate, expansion rate, etc. will all decrease significantly, and cations in seawater, such as calcium and magnesium ions, will interact with The monovalent cations in the montmorillonite (the main component of bentonite) crystals undergo ion exchange, which increases the gravitational force between the layers of the montmorillonite crystal, thereby reducing the gap between the layers, making it difficult for external water to enter, that is Reduced swelling properties of bentonite

[0004] The routine testing items for mud are only viscosity, specific gravity, colloid rate, sand content, etc. Generally, the expansion performance of bentonite particles is not tested, that is, there is no corresponding detection of the particle size of solid particles in the mud. Therefore, the current market for seawater Most of the mud conditioners are to improve the viscosity and colloid rate of the mud. No mud conditioner considers the influence of ions in seawater on the particle size of bentonite mud solid particles. Its essence is to increase the viscosity and colloid rate of the mud by introducing polymers, and The performance degradation of bentonite affected by seawater ions has not been solved, resulting in the entire mud industry selecting mud conditioners based on viscosity as an evaluation index, while ignoring the particle size distribution of mud