Analysis On The Effects Of Pre-reinforcement For Weak Surrounding Rock Of Tunnel Based On ADECO-RS

Making use of advanced core soil after reinforcement for tunnel stability is the core idea of ADECO-RS.The full face excavation based on pre-reinforcement principle of ADECO-RS has advantages of fast construction speed,high economic benefit and so on.In addition,this method has many successful applications in tunnel engineering that has the relatively poor geological conditions.But its theoretical study focus on the extrusion deformation of excavation face,the pre-convergence deformation and the convergence deformation,the impact on soil in front of the excavation face from the pre-reinforcement measures is often ignored.At the same time,combining with the current level of tunnel construction,the mechanization level and the complicated geological conditions in our country,full face excavation after the pre-reinforcement often cannot bring its efficiency and security.At present,some excavation methods and pre-reinforcement methods correspond to the principle of ADECO-RS.This paper made a detailed study focus on the impact on the plastic yield zone of soil in front of the excavation face from the pre-reinforcement measures and the applicability of full face excavation in soft surrounding rock.Detailed work is described as follows:(1)This paper systematically introduced the basic theory of the new method,and summarized the research and application status of the strengthening measures at home and abroad;(2)The stability of tunnel face principle was summarized and the factors influencing the stability of the excavating face was analyzed.An example was studied by establishing a horizontal slice in front of the excavating face,the relationship between the stability of excavating face and effect of core soil reinforcement.(3)By numerical simulation to the different operating modes,expounded the influence of pre-reinforcement measures on plastic yield zone development in the front of excavating face,influence of reinforcement length in different rock conditions on the plastic yield zone,excavating face extrusion displacement and so on systematically.(4)Short bench excavation combined with pipe-roof and full face excavation with using fiberglass anchor to pre-reinforce advanced core soil were analyzed under the different surrounding rock conditions,and the method of excavation under the condition of V grade and VI grade rock was proposed.Finally,the existing problems and the further direction of this reseach were discussed briefly.