胶结分层充填体抗弯特性试验研究  

Experimental Study on Bending Resistance of Cemented Layered Backfill

作　　者：秦旭忠 宋卫东[1,2] 曹帅[1,2] 郝益民 QIN Xuzhong;SONG Weidong;CAO Shuai;HAO Yimin(Civil and Resource Engineering School,University of Science and Technology Beijing,Beijing 100083,China;State Key laboratory of High-Efficient Mining and Safety of Metal Mines of Ministry of Education,University of Science and Technology Beijing,Beijing 100083,China)

机构地区：[1]北京科技大学土木与资源工程学院,北京100083 [2]北京科技大学金属矿山高效开采与安全教育部重点实验室,北京100083

出　　处：《矿业研究与开发》2020年第3期107-112,共6页Mining Research and Development

基　　金：国家自然科学基金项目(51804017);中国博士后基金面上项目(2018M631341).

摘　　要：为研究多层充填体的抗弯特性,用灰砂比为1∶4和1∶8的充填体料浆浇筑各料浆不同占比下的多层充填体试件,开展3点抗弯实验,同时借助颗粒流PFC2D软件进行相同尺寸试件的数值模拟,得出如下结论:当分层充填体的各料浆所占比重相等时,灰砂比为1∶4的充填料浆处于下层时的峰值荷载明显高于其处于上层时的峰值荷载;当灰砂比为1∶4的充填料浆处于上层时,随着其比重从25%增加至75%,峰后面积所占的比重从18%增加至80%,由此说明,当高灰砂比的充填体料浆处于上层时,可以极大地改善充填体的峰后抗弯性能,并且改善程度随着其比重的增加而愈发明显;试件在3点加载的弯曲破坏过程中,按颗粒的接触类型可以分为拉伸区和压缩区,试件的破坏主要是由颗粒间拉伸裂纹的产生和发育而引起的,并且随着裂纹的发育,其两侧颗粒之间的接触力迅速递减为0;分层充填体试件中上下层的分界线具有改变裂纹发育方向的作用,使其沿着分界线不断发育。To study the bending resistance of multi-layered backfill,the multi-layered filling specimens with different proportions of the slurry were poured by the filling slurry with the cement-sand ratio of 1:4 and 1:8.Then,three-point loading bending tests were carried out.And the specimens with same size were simulated by particle flow PFC2 D software.The following conclusions were drawn.When the proportion of each slurry in the layered filling body was equal,the peak load of the filling slurry with cement-sand ratio of 1:4 in the lower layer was significantly higher than that in the upper layer.When the filling slurry with cement-sand ratio of 1:4 was in the upper layer,the area proportion behind the peak increased from 18%to80%with the proportion increase of slurry from 25%to 75%.This indicated that the post-peak bending resistance of the filling body can be greatly improved when the filling slurry with high cement-sand ratio was in the upper layer,and the improvement degree became more apparent with the proportion increase of slurry.According to the contact type of particles,the specimen can be divided into tensile zone and compression zone in the bending failure process of three-point loading.The failure of specimen was mainly caused by the generation and development of tensile cracks among particles.With the development of cracks,the contact force among particles on both sides decreased rapidly to 0.The dividing line in the upper and lower layers of the layered backfill specimen can change the direction of crack development and make it develop along the dividing line.

关 键 词：分层充填体 抗弯特性 PFC2D 

分 类 号：TD853.34[矿业工程—金属矿开采]