饱和软黄土隧道围岩注浆加固参数研究

研究目的:饱和软黄土地层隧道围岩具有强度低、承载力差、抗变形能力弱等特性,因此对饱和软黄土地层隧道围岩注浆加固参数展开研究具有重要意义.依托西安地铁4号线火车站站暗挖西安火车站工程,进行室内黄土力学性能和现场注浆试验,研究含水率对黄土强度特性的影响,分析黄土劈裂注浆浆液扩散的基本规律及劈裂机理,并总结现场隧道围岩注浆加...

Research on the Grouting Reinforcement Parameters of Tunnel Surrounding Rock in Saturated Soft Loess

Research purposes: Tunnel surrounding rock in saturated soft loess has the characteristics of low strength,poor bearing capacity,weak deformation resistance,etc. So it is of great significance to study grouting reinforcement parameters of tunnel surrounding rock in saturated soft loess. Relying on the project of Xi’an Metro line 4 Huochezhan station undercutting railway station,the indoor loess mechanical properties and grouting test is conducted,the effects of water content on the strength properties of loess are studied,the basic law of grout diffusion and fracturing mechanism in loess fracturing grouting test are analyzed,and the grouting reinforcement parameters of the tunnel surrounding rock on construction site are summarized.Research conclusions:( 1) The water content of saturated soft loess decreases and its strength increases linearly,so after grouting,the permeability of undisturbed soils is reduced and the cohesion of the soil is improved,and the shear strength of the soil is improved overall.( 2) Basic law of grout diffusion and fracturing mechanism: angle of plasma vein is approximately 120°,and the height is inconsistent,the length is different. When the grouting pressure is gradually increased,the slurry will split the soil three times in the loess body,forming splitting cracks,and diffusing and filling them,and finally form the " Y" type vein of the loess fracture grouting.( 3) The unconfined compressive strength of the reinforced excavation surface soil reaches 0. 6 MPa, the strength of surrounding soil reinforcement area reaches1. 2 MPa,the permeability coefficient is no more than 10-6 cm/s,and the water content decreases from about 30% to10%.( 4) The paper obtained the parameters such as the mix ratio used for WSS grouting,the control value of grouting pressure,and the filling factor of loess in the project of saturated soft loess tunnel undercutting railway station,which can provide necessary reference for the precise design of grouting reinforcement parameters of tunnel surrounding rock in saturated soft loess.