摘要
为了提高锚杆抗拔力,研发了一种新型端部镦粗锚杆,镦粗部分能够显著提高侧摩擦面积,且受拉时端部与注浆体发生自锁。通过对新型锚杆和传统锚杆开展现场拉拔试验以及数值模拟分析,进一步揭示水泥强度、孔径、锚固长度和孔径等因素下新型锚杆的拉拔性能和锚固机理。试验结果表明,在黄土和煤矸石场地下传统和新型锚杆的破坏模式均为第二界面破坏,但破坏程度不同。新型锚杆可不同程度地降低对场地、水泥强度、孔径等条件的依赖,并且加设对中装置后抗拔力提升效果更为显著。采用颗粒流软件PFC2D研究了新型锚杆和传统锚杆的应力和破坏特征。模拟结果表明,拉拔过程中新型锚杆相较传统锚杆能够承担更大的应力,峰值应力增加幅度超过40%。新型锚杆端部水泥和土体内的应力显著高于传统锚杆,镦粗部分通过挤压水泥和土体能够显著提高新型锚杆的抗拉力。通过对比不同模型预测新型端部镦粗锚杆的Q-S曲线的有效性,其中指-幂函数模型能够更好描述新型端部镦粗锚杆的力学特性。
In this study,a new type of end-upset rock bolt was developed in the hope of enhancing the pullout resistance of rock bolts.The upset portion can remarkably expand the side friction area and a-chieve self-locking with the grout under tension.Through field pullout tests and numerical simulation a-nalysis on conventional and new rock bolts,the pullout performance and anchoring mechanism of the new rock bolt under different cement strength,borehole diameter,anchorage length,and hole diameter conditions were further disclosed.The test results indicate that the failure modes of both conventional and new rock bolts on loess and coal gangue sites are the second interface failure,but with varying degrees of severity.The new rock bolt corresponds to lower dependency on site conditions,cement strength,and borehole diameter to different extents,and its pullout resistance is significantly improved after the addi-tion of a centering device.Moreover,the stress and failure characteristics of conventional and new rock bolts were compared with the aid of particle flow software PFC2D.The simulation results suggest that the new rock bolt bears higher stress during pullout than the conventional rock bolt,with a peak stress increase of over 40%.In addition,the stress in the cement and soil at the end of the new rock bolt is much higher than that in the conventional rock bolt,and the upset portion can effectively raise the tensile force of the new rock bolt through cement and soil compression.By comparing the effectiveness of different models in predicting the load-displacement(Q-S)curve of the new end-upset rock bolt,it is found that the power-exponential function model can better describe the mechanical characteristics of the new endupset rock bolt.
作者
张晋玮
郑宏
张珣
ZHANG Jinwei;ZHENG Hong;ZHANG Xun(College of Architecture and Civil Engineering,Beijing University of Technology,Beijing 100124,China;Beijing Construction Engineering Group Co Ltd,Beijing 101117,China)
出处
《采矿与安全工程学报》
北大核心
2025年第4期768-778,共11页
Journal of Mining & Safety Engineering
基金
国家自然科学基金项目(52130905,52079002)。
