湿喷混凝土+树脂锚杆耦合支护的力学模型

Mechanical model of wet shotcrete + resin bolt coupling support

为探明树脂锚杆+湿喷混凝土对破碎岩体支护原理,合理确定喷锚支护参数,通过对巷道围岩和混凝土层进行受力分析,依据弹性力学理论,将树脂锚杆与混凝土层简化为固支梁力学模型进行解析,结合莫尔库伦强度理论,建立喷射混凝土层厚度、混凝土强度、锚杆间距对围岩自承能力影响的力学模型,并由此探明喷锚支护各参数与围岩自承能力的影响规律,进而对支护参数进行优化。研究结果表明:混凝土强度与围岩自承能力呈线性关系,而混凝土厚度与围岩自承能力呈指数函数关系,锚杆间距与围岩自承能力呈负指数关系。优化支护参数后,巷道稳定性增加,年垮冒次数降低77%,说明该模型具有良好的适用性。

In order to make clear the supporting principle ofbolt-shotcrete to broken rock mass and determine the support parameters reasonably, through the study of the stress analysis on roadway surrounding rock and shotcrete layer, the bolt and shotcrete layer were simplified as fixed-end mechanical models and combined with Mohr-Coulomb strength theory. The relation equation of the shotcrete layer thickness, the shotcrete strength arid bolt spacing with the surrounding rock self-supporting capacity was derived, and the action mechanism of bolt-shotcrete parameters to surrounding rock self-supporting capacity was obtained. The results show that the relationship between self-supporting capacity and shotcrete strength is linear, and exponential function relation with the shotcrete thickness, and negative exponential function relationship with bolt spacing. Based on the model, the support parameters are optimized, and the stability of tunnel increases and yearly rock fall times decrease by 77%, indicating that the mechanical model has good adaptability.