基于Erf时间函数的采空区地表后两期沉降动态预计

Dynamic prediction on goaf surface subsidence for the last two periods based on the Erf time function

  • 摘要:
    背景 煤层开采引发的地表沉降属于连续动态演化过程,采空区地表全时段沉降模型的构建对土地资源合理利用、工程建设安全保障及资源型城市转型发展具有重要理论与实践价值。
    方法 为实现采空区地表沉降衰退期与剩余期的精确预测,提出一种基于误差时间函数(Erf)的采空区地表沉降预测模型。首先,分析Erf时间函数的演化特性,验证该模型在沉降量、沉降速度及沉降加速度方面均符合采空区地表沉降的内在规律;其次,基于扩展窗口法(EWM)构建时间函数参数求解模型,采用Logistic、Usher及Erf等时间函数对参数求解结果进行验证与取值修正,实现利用初始期与活跃期监测数据对衰退期及剩余期沉降量的精准推演;最后,采用河北钱家营煤矿1176E工作面和山西常村煤矿S3-13工作面的现场监测数据开展实例验证,分别通过非参数化与参数化方法对最大沉降量进行预测。
    结果和结论 2种预测方法的整体误差水平一致,最大预测误差仅为4.74%,且误差随时间演化呈逐渐减小趋势;其中,非参数化预测误差主要源于理论计算偏差及时间函数的过早收敛,而参数化预测误差更小,其误差主要由时间函数预测模型自身的函数特性决定。通过对衰退期及剩余期沉降量的理论推演,提出沉降衰退期与剩余期的沉降盆地模型预计方法,基于该方法构建三维沉降模型,最终实现了采空区衰退期与剩余期地表沉降的精确预测,为采空区地表沉降全时段预测提供了新的技术路径与理论支撑。

     

    Abstract:
    Background The surface subsidence induced by coal seam mining represents a continuous dynamic evolution process. Constructing a full-time perdition model for surface subsidence in goafs holds significant theoretical and practical values for the rational utilization of land resources, the safety guarantee of engineering construction, and the transformation and development of resource-based cities.
    Methods To accurately predict the surface subsidence in goafs during its decline and residual periods, this study proposed a prediction model based on the error function (Erf). First, the evolution characteristics of Erf were analyzed, verifying that the subsidence, as well as its velocity and acceleration, predicted using the model conformed to the inherent laws of surface subsidence in goafs. Second, a model for determining the parameters of the Erf function was developed based on the expanding window method (EMW). Then, the parameter solutions of the model were verified and corrected using time functions such as Logistic, Usher, and Erf. These efforts help accurately determine the surface subsidence during its decline and residual periods using monitoring data from the initial and active subsidence periods. Finally, field monitoring data from mining face 1176E in the Qianjiaying Coal Mine, Hebei Province, and mining face S3-13 in the Changcun Coal Mine, Shanxi Province, were used for verification. The maximum surface subsidence was predicted using non-parametric and parametric methods individually.
    Results and Conclusions The non-parametric and parametric prediction methods generally exhibited roughly consistent error levels, with errors trending downward over time and a maximum prediction error of merely 4.74%. The errors of the non-parametric prediction method arose primarily from theoretical calculation-induced deviations and the premature convergence of the time functions. In contrast, the parametric prediction method yielded smaller errors, which were primarily determined by the inherent functional characteristics of the Erf-based prediction model. Through the theoretical deductions of the subsidence in the decline and residual periods, a prediction method for the subsidence basin model in these two periods was proposed. Using this method, 3D subsidence models were constructed, ultimately achieving the accurate prediction of surface subsidence in goafs during the two periods. The results of this study provide a new technical pathway and theoretical support for the full-time prediction of surface subsidence in goafs.

     

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