The Appraisal Of Improving The Soil Condition Of EPBS With New Foam

In a variety of excavation methods, earth pressure balance shield method iswidely applied in underground engineering due to its proper advantages of highermechanization, safe and fast construction, and fine quality, etc. At present pressurebalance shield method has become the mainstream of tunnel construction.The key factor to success in EPBS is converting the muck which is lack offluidity excavated from the cutter face to the plasticity soil. But presently, there is nofoaming agents in our country and all foaming agents in EPBS are foreign products,so the price is very high, and there is no evaluation method of foam agents in EPBS.In response to this technical problem, this paper developed a new type of earthpressure balance shield foam and the results of indoor tests and field experimentsappraise the effect.This paper studies the content of the following:(1) The paper select several surfactants that are economic and environmentalprotection. From two technical indicators which are half period and the foamingvolume, evaluated the performance of the select surface-active agent, obtain theoptimal mixture ratio and developed a new type of foam.(2) Through the indoor mixing test, skateboard test, bucket test, mud test anddirect shear test for new foam modifier and evaluate the effect of different soilimprovement and give a quantitative analysis of the improvement effect(3) On the basis of the indoor tests, in order to prove the performance of the newfoam and the improvement effect on soil, we made field test.