厚冲积层薄基岩采场围岩三维力学特征

采用相似条件采场类比、现场实测和数值分析综合研究方法，研究了厚冲积层薄基岩采场围岩三维力学特征，研究表明：厚冲积层薄基岩采场矿压显现与基采比密切相关，随着基采比增大，采场矿压趋于缓和。按基采比大小可将采场划分为“有板有壳”、“有板无壳”和“无板无壳”3种类型。“有板有壳”类型采场，应力壳为采场第1掩体，其下位的断裂带板（梁）结构为第2掩体，采场矿压显现缓和；“有板无壳”类型采场，断裂带板（梁）结构为采场惟一掩体，其上位无“应力壳”承载，板（梁）结构失稳后采场矿压显现剧烈；“无板无壳”类型采场，无板（梁）结构和“应力壳”的掩护，冲积层荷载直接传递在液压支架上，该类采场易发生压架事故。“无板无壳”类型采场的覆岩结构沿竖向划分为两带，即“垮落带”和“弯曲下沉带”。并对形成3种类型采场的力学机理进行分析。

Three-dimensional mechanical characteristics of rocks surrounding the stope of thick unconsolidated layers and thin bedrock

Three-dimensional mechanical characteristics of rocks surrounding the stope of thick unconsolidated layers and thin bedrock were studied using the comprehensive research methods of similar conditions stope analogy，field measurement and numerical calculation.Draw the following conclusions：strata behaviors is related to the base-mining ratio，with the base-ming ratio increasing，strata behaviors is easing.According to the different base-mining ratio，stope can be classified as three types，including “having plate and shell”，“having plate without shell” and “no plates no shell”.For the “having plate and shell” type of stope，“stress shell” is first shelter of the stope，and rock beams or plates in fractured zone as second shelter of the stope，strata behaviors easing；For the “having plate without shell ” type of stop，rock beams or plates in fractured zone are first shelter of the stope，without upper bearing stress shell，if the structure of plates or beams is instability，strata behaviors of the stope is dramatic；For the “no plate no shell” type of stope，neither the structure of plates or beams nor “stress shell” shelter，alluvial soil load transfer on the hydraulic support directly，this is the important reason that the stope of small base-mining ratio is prone to happen the fully mechanized support crushing accidents.The overlying strata of “no plate no shell” type of stope according to rock vertical structure are divided into two zones，namely “caving zone” and “bending zone”.And the mechanics mechanism of formation of three types of stope are analyzed.