Study on the influence of water-cement ratio in cement-based grouting materials on the settlement control of weak tunnel surrounding rock
YAO Jun
LONG Chao
LIU Hao
Abstract：Tunnel excavation in weak surrounding rock masses is susceptible to geological hazards such as stra-tum settlement and surface collapse.Grouting reinforcement is frequently utilized in engineering practice to en-hance rock mass strength.The injection of cement grout under pressure into the surrounding rock increases its strength upon hardening,with the water-cement ratio significantly affecting the mechanical properties of the grouted zone.This study examines weak surrounding rock in tunnels by preparing cement grouts with varying water-cement ratios(ranging from 1∶1 to 2∶1)for soil reinforcement.Direct shear tests were performed to as-certain the shear strength parameters(internal friction angle and cohesion)of improved soils.The obtained data were subsequently incorporated into an ABAQUS-based numerical model for analyzing tunnel excavation-induced settlement.Key findings include:(1)The shear test results indicate that soil strength is enhanced post-grouting,revealing an inverse relationship between water-cement ratio and shear strength;(2)Grouting reinforcement effectively mitigates excavation-induced settlement,with the 1∶1 water-cement ratio resulting in a surface settlement of 8.22 mm,which complies with code requirements.These findings provide theoretical guidance for grouting design in conditions of weak surrounding rock.
Keywords：cement-based grouting materialwater-cement ratiodirect shear experimentsettlementnumerical analysis
Publication Date：2025-10-30
Online Publishing Date：2025-11-06(First online date of this platform, not the publication date of the document)
Pages：8( 60-67 )