冻融作用下水灰比对类岩石材料物理力学特性影响研究

高寒地区矿山边坡岩体会经历冻融循环作用，引起岩体结构损伤和强度弱化，对矿山边坡的稳定性构成危害。水泥砂浆作为模拟裂隙边坡岩体常用的类岩石材料，其配合比对该类岩石材料抗冻性影响较大。为探究冻融作用下水灰比对类岩石材料物理力学特性的影响机制，制作了7种不同水灰比的类岩石——水泥砂浆标准试样，进行了不同次数的冻融循环试验及0~50次冻融后的单轴压缩试验。结果表明：①冻融前，随着水灰比的增大，试样初始孔隙率增大、密度降低，进而导致其波速下降；冻融过程中，波速随着冻融次数的增加而减小，且水灰比越大，波速损失率越高。②随着水灰比增大，类岩石材料的单轴抗压强度、弹性模量均出现了先增大后减小的现象；当水灰比为0.325~0.35时，类岩石试样的单轴抗压强度最高且抗冻性能最好。③随着冻融循环次数增加，应力应变曲线趋于扁平化，试样由脆性逐渐向延性转化，且水灰比越大，试样孔隙压密阶段变形越大。研究成果可为寒区矿山边坡及相关岩体工程类裂隙岩体冻融试验中的配比设计提供借鉴。

Study on the Method of Rock Movement Control in Mengjiapuzi Iron Mine

After the open-pit mining of the Mengjiapuzi Iron Mine is completed，the ore body below the level of +70 m is mined by the sublevel caving method.As the underground mining progresses，the overburden has already caved to the bottom of the open pit，formed a large-scale surface collapse pit，the rock movement posed a serious threat to the surface office and shaft.At present，the remaining waste rock cannot meet the filling requirements of surface collapse pits， and the development of rock movement along the side wall of the collapse pit cannot be effectively controlled.In order to solve this technical problem，according to the support principle of critical medium column，this paper studies the new rock movement control method of tailings instead of waste rock filling surface collapse pit，the characteristics of tailings penetration under different tailings concentration and particle size distribution are obtained，the prediction expression of tailings mixed height affected by the drop height of the loose body is given.The study results show that the tailings height of the concentration range of 70%~80% is 130.76~42.36 m，and the mixed height of tailings in this concentration range is smaller than the minimum thickness of the bulk layer in the collapse pit，it is safe and feasible to fill the surface collapse pit with this concentration range. Finally we determine that the reasonable tailings filling concentration on the site is 75%~80%.It is safe and feasible to use the tailings to fill the surface collapse pit， and the reasonable tailings filling concentration is 75%~80%.In order to ensure the safe and smooth operation of the filling operation，the study divides the collapse pit into a slope filling area and a full filling area，and proposes a three-way coordinated filling method along the axial and radial directions of the collapse pit，which provides a strong guarantee for the safe， green and efficient mining.