基于改进组合弹簧模型的矿井地应力场计算方法

Calculation of mine in-situ stress field based on the improved composite spring model

地应力场是影响围岩稳定性的重要因素,准确反演计算地应力场是采矿工程设计中的难点。结合布尔台矿Kaiser法实测地应力数据,提出了一种基于改进组合弹簧模型的地应力场计算方法,并与侧压系数法、经典组合弹簧模型法等的结果和实测值进行了对比。利用FLAC^(3D)研究了不同侧向应力边界条件下布尔台矿42105工作面矿压显现规律,并与实测矿压数据进行了对比分析。研究结果表明:所提出方法计算的应力场与实测值间主应力均方根平均误差均值为1.831,较其他反演计算方法降低了14.6%~42.2%;对称平均绝对百分比误差均值为19.45%,较其他反演计算方法降低了3.4%~36.9%。将该方法计算的应力作为应力边界时,模拟得到的支撑力与实测数据间的均方根误差的平均值为66.55,相较于侧压系数法降低了7.75%,相较于经典组合弹簧模型法降低了32.45%;对称平均绝对百分比误差的平均值为15.75%,相较于侧压系数法降低了6.61%,相较于经典组合弹簧模型法降低了20.67%。因此,该方法能够较准确计算地应力场并为精准模拟矿压规律提供新的应力边界施加方法的参考。

The in-situ stress field is an important factor affecting the stability of surrounding rock,and accurate-ly inverting the stress field is difficult in mining engineering.Based on the Kaiser method for measuring in-situ stress data at the Buertai Mine,a calculation method for the stress field based on an improved combined spring model is proposed,and the results are compared with the results and measured values of the lateral pressure coefficient method and the classical combined spring model method.Using FLAC^(3D),the stress dis-tribution law of the 42105 working face in the Buertai mine under different lateral stress boundary conditions was stud-ied,and compared with the measured stress data.The research results show that:the root mean square average error of the main stresses between the calculated stress field and the measured values using this method is 1.831,which is reduced by 14.6%to 42.2%when compared to other inversion calculation methods;the average sym-metric absolute percentage error is 19.45%,which is reduced by 3.4%to 36.9%when compared to other inver-sion calculation methods.When the stress calculated by this method is used as the stress boundary,the average root mean square error between the simulated support force and the measured data is 66.55,which is reduced by 7.75%when compared to the lateral pressure coefficient method and 32.45%when compared to the classical combined spring model method.The average symmetric absolute percentage error is 15.75%,which is reduced by 6.61%when compared to the lateral pressure coefficient method and 20.67%when compared to the classical combined spring model method.Therefore,this method can accurately calculate the stress field and provide a reference for the precise simulation of the mining pressure law by providing new methods of applying stress boundaries.