全长锚固系统失效机制及耐久性探究

发布时间：2018-01-11 16:27

  本文关键词：全长锚固系统失效机制及耐久性探究　出处：《中国矿业大学》2017年博士论文　论文类型：学位论文

  更多相关文章： 全长锚固 拉拔试验 预应力支护 失效机制 声发射

【摘要】：为揭示全长锚固系统的失效机制,本文基于理论分析、实验室测试、现场实践探讨了决定全长锚固系统耐久性的主要因素。研究涉及了锚固对象承载力修复细观机理、锚固界面的渐进损伤过程以及岩层离层下的损伤过程、全长预应力锚固的可靠性测试及实施、分段钢管锚固下的锚固失效机制、以及循环载荷下锚固系统耐久性评价,最后对全长锚固系统的发展方向做以简要展望,主要结论如下:(1)提出了一种新型注浆树脂材料来实现全长锚固,并采用这种材料对常见煤系地层的煤样和砂岩试样进行了峰后强度修复测试。测试表明该注浆树脂在加固碎裂煤岩体方面有一定优越性,同时提出了实现全长锚固的具体流程。对全长锚固系统锚固剂-围岩黏结界面的失效机制进行了分析研究,提出了渐进式的失效特征,对不同黏结状态下的界面剪力和轴力分布形式展开了理论分析,从界面黏结状态改变的角度上探讨了锚固力骤降机制。(2)研究表明层状顶板离层条件下锚固界面保持其弹性状态时对应一个临界离层宽度。未超过离层宽度时,界面剪应力分布对离层位于锚固系统中的具体位置不敏感,锚固系统也相对稳定;超过该宽度后,离层两侧界面的黏结状态将发生改变且对离层位置变动较为敏感。当离层位于锚固系统端头位置附近时,锚固系统受到的影响最大,而位于尾部时,受到的影响最小。实验室测试验证了离层两侧界面剪力分布的合理性。(3)研究提出一种新型水泥基锚固袋来实现预应力全长锚固。实验室拉拔测试表明预拉力全长锚固系统相较于传统端锚更稳定,承载力更强。声发射测试表明预拉力的升高带来损伤事件总数的降低,且事件分布逐渐向杆体自身和锚固端头方向迁移,高预拉力条件下决定全长锚固系统承载性能的为杆体抗拉强度。研究成果在青海能源大通煤矿得到成功应用,围岩变形控制效果显著。(4)为模拟不同厚度互层岩体下锚固系统失效特性,研究了由不同分段钢管通过端面黏结形成的组合钢管在锚固拉拔作用下的分离机制。研究认为锚固系统的失效形式、拉拔力波动特点、拉拔力和拉拔位移大小都和钢管夹持端的分段钢管长度有紧密关联,研究同时提出了钢管内应力分布的理论模型。(5)探讨了不同直径锚杆锚固系统在循环载荷下的动力响应特性。实验证实了锚固钢管内合理的应力分布形式,特定循环模式下锚固系统也具有“变形记忆”特性和流变特性,但是较难观察到类似于岩石在循环动载下所表现出的“塑性滞回环”特征。锚固系统的失效形式与锚固方式、循环动载特性都有很大关系。
[Abstract]:In order to reveal the failure mechanism of full-length anchoring system, this paper is based on theoretical analysis and laboratory testing. The main factors that determine the durability of the full-length anchoring system are discussed in the field practice. The research involves the meso-mechanism of the bearing capacity of the anchoring object, the progressive damage process of the Anchorage interface and the damage process under the rock layer. The reliability test and implementation of full-length prestressed Anchorage, the failure mechanism of Anchorage in segmented steel tubes, and the durability evaluation of Anchorage system under cyclic load are also discussed. Finally, the development direction of Full-length Anchorage system is briefly prospected. The main conclusions are as follows: (1) A new grouting resin material is proposed to achieve full-length anchoring. The post-peak strength of coal samples and sandstone samples in common coal measure strata were tested by this kind of material. The test results show that the grouting resin has some advantages in strengthening fractured coal and rock mass. At the same time, the concrete flow of full-length anchoring is put forward. The failure mechanism of anchor-surrounding rock bond interface of full-length anchoring system is analyzed and studied, and the progressive failure characteristics are put forward. The distribution of interfacial shear force and axial force in different bonding states is analyzed theoretically. The mechanism of sudden drop of anchoring force is discussed from the point of view of the change of interfacial bonding state. The results show that when the Anchorage interface keeps its elastic state under the condition of layered roof separation, it corresponds to a critical layer width, which does not exceed the layer separation width. The interfacial shear stress distribution is not sensitive to the specific position of the separated layer in the Anchorage system, and the Anchorage system is relatively stable. When the width exceeds, the bonding state of the interface between the two sides of the separation layer will change and be sensitive to the change of the location of the separation layer. When the layer is located near the end of the Anchorage system, the Anchorage system will be most affected. And at the end. The effect is minimal. Laboratory tests verify the rationality of shear distribution at the interface between the two sides of the separation layer. A new cement-based anchoring bag is proposed to realize the full-length prestressed anchoring. The laboratory pull test shows that the full-length pre-tension anchoring system is more stable than the traditional end-anchor system. The acoustic emission test shows that the increase of pretension force leads to the decrease of the total number of damage events, and the distribution of the events gradually moves to the direction of the rod itself and the anchoring end. Under the condition of high pretension, the bearing capacity of the full-length anchoring system is determined by the tensile strength of the rod body. The research results have been successfully applied in Qinghai energy source Datong coal mine. The deformation control effect of surrounding rock is significant. 4) the failure characteristics of anchoring system under interbedded rock mass with different thickness are simulated. The separation mechanism of composite steel pipe formed by different sections of steel pipe through end bonding under the action of anchoring and drawing is studied. The failure form of the anchoring system and the characteristics of pull-out force fluctuation are considered. Drawing force and drawing displacement are closely related to the length of steel pipe at the clamping end. At the same time, a theoretical model of stress distribution in steel pipe is proposed.) the dynamic response characteristics of anchoring system with different diameters under cyclic load are discussed, and the reasonable stress distribution in anchored steel pipe is verified by experiments. Anchorage system also has the characteristics of "deformation memory" and rheology under specific cyclic mode. However, it is difficult to observe the characteristics of "plastic hysteresis loop" similar to that of rock under cyclic dynamic load. The failure form of anchoring system is closely related to anchoring mode and cyclic dynamic load characteristic.
【学位授予单位】：中国矿业大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TD353.6
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本文编号：1410316