基于中性区特征的沿空掘巷煤柱宽度分析与实践

Analysis and practice of coal pillar width of gob-side entry driving based on neutral zone features

煤柱宽度是沿空掘巷技术的主要参数,对于留巷成功与否有关键作用;煤柱的稳定可以采用煤柱水平变形的中性区特征进行描述,中性区的大小以及承载能力变化能够表征煤柱的稳定程度。根据典型工程背景和护巷煤柱的中性区理论,建立数值模型模拟分析不同宽度煤柱内中性区的变化和承载力特征。研究发现:随煤柱宽度增加,煤柱内中性区的宽度逐渐增加,煤柱的承载能力也逐渐增加,但中性区宽度占比表现出先增加后减小又增加的规律,煤柱承载能力的增加率则为先升高后降低;煤柱宽度6~7 m时存在满足条件的稳定承载区;综合理论计算、数值模拟和现场条件确定煤柱合理宽度为6 m。

The coal pillar width is the main parameter of gob-side entry driving technology, which plays a key role in the success of roadway retention. The stability of the coal pillar can be described by the features of the neutral zone of the horizontal deformation of the coal pillar. The size of the neutral zone and the change of the bearing capacity can characterize the stability of the coal pillar. Based on the typical engineering background and the neutral zone theory of the coal pillars of roadway protection,a numerical model was established to simulate and analyze the change characteristics of the shape of the neutral zone and the bearing capacity in the coal pillars with different widths;as the width of the coal pillars increases, the width of the neutral zone in the coal pillars gradually increases, and the bearing capacity of the coal pillars also gradually increases, but the proportion of the neutral zone width first increases, then decreases and then increases. The increase rate of the coal pillar bearing capacity first increases and then decreases. The coal pillar could keep stability when the width is 6-7 m. The comprehensive theoretical calculation, numerical simulation results and field conditions determine that the reasonable width of the coal pillar is 6 m.