Papers by Keyword: Broken Rock

Abstract: According to the model tests of the broken rock behind the tunnel lining impacting on the structural safety, and numerical simulation studying the tunnel in 3 different stress fields while the broken rock locates 2 different positions, the article studies the safety of tunnel structure. The results showed that: in a uniform stress field, the lining played a maximum carrying capacity whenever the broken rock on the vault or behind the right side of the wall. In the horizontal pressure based stress field, when broken rock is on the vault, the grouting effect is most significant and the negative moment was controled by the rate of 75%. In the vertical pressure based stress field, when the broken rock is behind the right side wall, the disease spread sporadically throughout the arch after grouting.

Abstract: The high-moisture quick-concreting material is a special type of cement which can be quick-concreting and full solidifying under the condition of high water cement ratio (2.5 : 1 ) . Thus , the mechanical performances of high-moisture quick-concreting material are as follows : 1) The grout fluidity is better and the penetrability is strong ; 2)The volume of concretion is tiny expansion in favor of solid filling in steel tube and exiguous gap ; 3) Concreting speed is rapid and the early strength is big , and the concreting speed may be also adjusted ; 4)The water cement ratio and the mixing ratio can be changed to meet requirement of different strengths ; 5)There is a good plasticity . The residual strength of concreting body may account for about 50% of the peak value strength if the uniaxial compressive strain reaches to 15% ; 6) As a result of the big water cement ratio , little dosage of the unit volume and low price , the cost for using high-moisture quick-concreting material to reinforce the foundation pit wall and ground base and to fill the steel tube is lower. In this study , the mechanical property and concreting mechanism of high-moisture quick-concreting material to reinforce the loose coal body are studied and analysed by the field test and laboratory test . The test results indicated that there is a notable effect to consolidate roadway , foundation pit wall and ground base by grouting of high-moisture quick-concreting material . Finally , the engineering example of grouting by using the high-moisture quick-concreting material is presented.