碱化长径稻草改性铁尾矿水泥充填材料性能研究

Performance Study on the Iron Tailing Cement Filling Material Modified by Alkalized Long-Diameter Rice Straw

深井充填体面临高地应力和高岩层温度的复杂地下环境时,容易出现开裂、失稳、变形、强度衰减等现象,进而诱发巷道变形、冒顶、突涌水、垮塌等地质灾害。为确保充填体的力学性能和稳定性,将碱化长径稻草作为改性材料掺入充填料浆中改善其力学性能,为探明稻草掺量和稻草长度与充填料浆流变性能和力学性能的变化规律,设计16组正交试验,借助R/S-SST型软固体流变仪测试其流变参数,应用Hershel-Bulkley模型进行拟合分析。研究结果表明:随着稻草掺量和稻草长度的增加,水化产物的包裹及絮凝作用形成的干涉沉降絮团越多,料浆黏度和屈服应力不断增大,当稻草掺量为0.65%和稻草长度为9 mm时,充填体抗压强度增加效果明显,稻草在充填体中发挥纽带作用,增加了充填体黏结和机械咬合力;继续增加稻草掺量和稻草长度,单位体积内分散的稻草数量过多,充填体形成应力集中区,削弱了充填体抵抗变形的能力,从而降低了充填体力学性能。

When facing the complex underground environment of high geostress and high rock layer temperature,the deep well filling body is prone to crack,instability,deformation,strength attenuation and other phenomena,which will lead to geological disasters such as roadway deformation,roof fall,water inrush and collapse.In order to ensure the mechanical properties and stability of the filling body,alkalined long-diameter rice straw was added into the filling slurry as a modified material to improve its mechanical properties.In order to find out the influence rule of the amount and the length of rice straw on the rheological properties and mechanical properties of filling slurry,16 groups of orthogonal tests were designed.The rheological parameters were tested by the R/S-SST soft solid rheometer,and the Hershel-Bulkley model was used for fitting analysis.The results show that with the increase of the amount and the length of rice straw,the more interference settlement flocs formed by the encapsulation and flocculation of hydration products,the higher the slurry viscosity and yield stress.When the amount of rice straw is 0.65%and the the length of rice straw is 9 mm,the compressive strength of the filling body increases significantly,and the rice straw plays a bonding role in the filling body,which increases the bonding and mechanical bite force of the filling body.If the amount and the length of rice straw continue to increase,the number of dispersed rice straws per unit volume is too much,and the filling boby forms a stress concentration zone,which weakens the ability of the filling body to resist deformation and thus reduces the mechanical properties of the filling body.