地应力下缓胀锚固剂对锚固力提升的研究

Study on Enhancement of Anchoring Force by Slow Expansion Anchor Agent under Ground Stress

为了解决锚杆从锚固剂中脱锚的问题,研究了一种缓胀锚固剂,利用锚固剂的膨胀提高锚固力。通过弹性力学理论计算,推导了地应力下极限膨胀压力和安全膨胀剂掺量的计算公式;结合理论计算和扩展有限元法,得出了伊田煤业11#煤顶板的安全膨胀剂掺量;提出了膨胀剂掺量和拉拔力的关系式,并通过锚杆拉拔实验验证了膨胀剂掺量对拉拔力的影响规律。结果表明:缓胀锚固剂可以显著提高锚杆的锚固力,锚杆拉拔力随膨胀剂掺量增加而增大;针对伊田煤业11#煤顶板,确定了安全膨胀剂掺量为42%,拉拔力理论值可提升89.32%;拉拔力实测值均高于理论计算值,且随着膨胀剂掺量的增加,绝对误差与相对误差均逐渐增大,分析原因为膨胀压力加剧了机械互锁效应。

To solve the problem of bolt de-anchoring from the anchor agent,a slow expansion anchor agent was studied,which utilized expanding of anchor agent to enhance anchoring force.Through theoretical calculationof elastic mechanics,the calculation formulas of limit expansion pressure and safe expansion agent dosageunder the ground stress were deduced.Combined with extended finite element method,the ultimate expansion pressure for the No.ll coal roof of Yitian coal industry was verified and the safe expansion agent dosagewas calculated.The relationship equation between expanding agent dosage and pull-out force was proposed,and the influence law of expanding agent dosage on the pullout force was verified by pull-out experiment.Results show that the slow expansion anchor agent can enhance anchoring force significantly,and the pullout force increases with increasing expansion agent dosage;in view of No.1l coal roof of Yitian coal industry,the safe expansion agent dosage is determined to be 42%,and the theoretical value of the pull-out force can be increased by 89.32%;the measured values of pull-out force are higher than theoretical calculated values,and with the increase of expansion agent dosage,the absolute error and relative error both increase gradually,analyzing the reason is that the expansion pressure exacerbates the mechanical interlocking effect.