Model Experimental Study On Tunnel Pipe Grouting In Sandy Layers

The paper is based on Wangkeng tunnel engineering of Ji-Shao highway in Henan province, for there exist problems of grouting amount among different pipes vary great in the pipe grouting engineering, which is carried out in sandy layers in the left tunnel exit. Several possible impacts, such as Geological, design, construction and serous, were analysed.Accord to existing research results, indoor model test is not only a useful complement to theory study about pipe grouting, but also a theoretical basis for engineering practice. Through comparative analysis of several research methods about grouting, model test has several advantages, for the whole process of grouting can be observed, the distribution of slurry can be seen intuitively, the complex conditions of grouting parameters and other geological, water factors can be simulated. Take the tunnel construction site and geological factors to be considered, indoor model test also has other advantages. For example, the test material and equipment required for the test can be processed convenient, material consume less, higher economic. For another fact, model test can be operated simply and convenient, and its repeatability is strong. Thus this paper use the method of indoor model test to study runnel pipe grouting.To carry out the model test in sandy layers, referred to home and abroad research results about pipe grouting through the method of model test, the test model, the grouting system and the grouting programs must be designed independently. As several studies about ordinary portland slurry, test model,grouring model test and pipe grouting on-site been studied, the main findings as following:1. Test device and grouting system, suitable for grouting model test in sandy layers, were designed independently, and the model test was carried out successfully.2. Pipe grouting by using ordinary portland cement in sandy layers, the main factors affect grouting quantity and proliferation radius are water-cement ratio,grouting pressure,rock porosity,etc.Among the factors, water-cement ratio is the most significant factor, which affect slurry grouting ability, stability and controllability. In actual grouting engineering, we can adjust the grouting program by changing water-cement ratio.3. Grouting quantity and proliferation radius increase as grouting pressure increased. Because of uneven rock and porosity,etc.,the distance of slurry range and spread various tremendous.4. Adjacent pipes affect the soil mutually as they work complement and combined with each other. They work as skeleton in soil and encrypt soil. In the process of grouting, pipe should be grouted every other or every row, grouting should complied with the order from outside to inside, thus the solid body formed overall better and its strength more higher.Due to time limited, this study only relates to the effects of water-cement ratio and grouting pressure ratio and the effects of grouting to grouting. For a number of other issues, such as how to design model test on other stratum and geological factors, how to use other types of material in grouting model experimental, how to do model test research on the case of considering groundwater influent, etc., which are often encountered in practical engineering, follow-up research will be done in depth.