Experimental study on optimization of pipe jacking mud mixture ratio based on MICP technology.

Area of Science:

• Geotechnical Engineering
• Biotechnology
• Construction Materials Science

Background:

• Pipe jacking construction faces challenges like excavation unloading and soil adhesion, impacting stability.
• Pipe jacking slurry is crucial for friction reduction and strata support during tunneling.
• Existing slurries require enhancement to improve performance and soil stabilization.

Purpose of the Study:

• To integrate Microbial-Induced Calcium Carbonate Precipitation (MICP) technology into pipe jacking slurry.
• To enhance the friction-reduction capabilities of the slurry.
• To improve the stability of the soil surrounding the pipe during jacking operations.

Main Methods:

• Determined optimal MICP-slurry formulation using uniform design.
• Conducted model tests to evaluate friction reduction efficacy.
• Investigated strata reinforcement mechanisms using soil mechanics and Scanning Electron Microscopy (SEM).

Main Results:

• Optimal MICP-slurry composition identified: bentonite: sodium carboxymethyl cellulose: soda ash: polyacrylamide: xanthan gum = 12%: 0.31%: 0.36%: 0.25%: 0.54%.
• MICP-slurry reduced the friction coefficient by 42.2%.
• MICP treatment increased soil cohesion by 38.12% and internal friction angle by 14.01%.

Conclusions:

• MICP-slurry effectively reduces friction and enhances soil mechanical properties in pipe jacking.
• Calcium carbonate precipitation by MICP fills soil pores, increasing inter-particle forces and improving stability.
• This technology offers a promising solution for improving pipe jacking construction efficiency and safety.