锚杆无损检测技术及其在工程中的应用

为了明确实测波形跟锚固质量、检测方式之间的关系，基于应力波反射法检测的原理、方法以及应力波的传播理论，针对不同检测要素，分别进行了锚杆模型试验、锚杆检测工作模式试验、锚杆固结前后试验，并结合工程实例，分析探讨了无损检测技术在锚杆锚固质量评价中的应用．     

锚杆锚固质量无损检测理论研究与应用

基于锚固体系的锚杆动力学及应力波运动学理论,研究了锚固体系的振动特征和锚固体系中瞬态应力波传播的能量衰减规律,进而提出瞬态应力波法是检测锚杆锚固质量的一种快速、便捷、可靠的无损检测方法。它是通过锚杆锚固质量检测仪接收瞬态应力波反射信号,通过数据信号分析,从而获得表征锚杆锚固质量的一系列参数,即锚固长度、波速及密实度。文章论述瞬态应力波法的基本原理及传播特征,并结合工程实例总结检测规律。     

锚杆锚固质量无损检测技术研究

基于锚固体系的锚杆动力学和一维波动理论，研究了锚固体系的振动特征和锚固体系中应力波的传播规律，进而提出了快速检测锚杆锚固质量的应力波反射法，并实际运用于太原东山煤矿巷道锚杆施工质量的检测．     

锚杆锚固质量检测在铁路工程中的应用

锚杆锚固技术在边坡支护和隧道施工中已经普遍使用,作为隐蔽性的重要工程,对其质量进行检测是非常必要的。结合工程实例,对同一组锚杆同时进行应力波反射法及拉拔试验,通过对锚杆密实度、缺陷位置及长度进行分析,并对比锚杆的密实度与拉拔伸长量成果。结果表明,应力波反射法可判断锚杆质量类别,锚固密实度与拉拔伸长量呈反比关系,证明应力波反射法在铁路工程锚杆锚固质量检测中的应用切实可行,可为边坡支护和隧道工程锚杆质量提供更好的保障。     

锚杆无损检测技术在水电站工程中的应用与探索

锚杆锚固质量无损检测法——超声波反射法,或称音频应力波反射法,包括锚杆长度检测和灌浆密实度检测两方面,其理论依据是一维波动理论。本文选取了具有典型代表的工程锚杆和试验锚杆进行了检测、分析和对比,结果表明无损检测是一种十分有效的检测技术,能成功有效地对锚杆锚固质量进行检测和分级,确保了工程质量。     

基于声频应力波法的隧道锚杆无损检测应用研究

锚杆的锚固质量关系到锚固结构的安全性,对其进行安全可靠的检测至关重要,根据无损检测理论,通过对应力波在一维杆结构体系传播的规律分析,由施工工艺缺陷在无损检测中的波形来判断锚杆的长度以及密实度情况。对某隧道工程10根?25的中空注浆锚杆的无损检测,检测结果与实际情况没有太大差异。分析表明基于声频应力波法的锚杆无损检测是可行的,声频应力波法能快速、准确地检测出锚杆质量。     

电磁法检测锚固质量初探

近年来,锚杆、锚固质量的无损检测技术得到了较快的发展,目前的研究主要集中在应力波反射法上,但该方法还需要进一步的研究,以解决应力波反射信号变弱甚至消失后的问题。本文讨论了一种新的锚固质量无损检测方法——“电磁法”。在最简化物理模型基础上推导出对锚杆加载交变电流时地面磁感应强度分布规律的公式,据此正演计算并作出了几组磁感应强度归一化曲线,提出磁感应强度曲线计算机拟合反演方法可望检测出空锚段比例和空锚段的位置,成为锚固质量检测的一种新的技术方法。     

锚杆锚固质量检测方法及应用

对锚杆锚固质量的检测一直为工程界所关注,本文比较了拉拔试验与声波反射检测锚杆锚固质量的方法,介绍了两种方法的基本原理以及相关的技术规定。鉴于拉拔试验方法上的不足,详细阐明了声波检测方法及其基本原理,并列举了应用于某高速公路隧道工程检测锚杆锚固质量检测的例子。     

基于柱状多层介质模型的锚杆锚固质量声波检测理论正演研究

针对当前锚杆质量检测理论存在的一些问题,提出以柱状多层固体介质模型为基础研究声波在锚杆-锚固介质-围岩体系中的传播规律,并在该模型条件下进行了数值计算.结果表明,基于柱状多层介质模型的理论用于锚杆锚固质量检测是可行的,实际工作中可以利用其特征参数对锚杆锚固质量进行评价.对于锚杆长度,可以通过反射波旅行时间给予确定;对于水泥胶结情况,可以利用地层波的幅度变化和导波模式波（高频）的特征确定.     

锚杆(索)锚固质量无损检测技术的研究现状与展望

针对锚杆(索)锚固质量的检测问题,列举和对比了无损检测的各种方法。在分析应力波无损检测影响因素和各种检测技术优缺点的基础上,阐述了无损检测的数据处理方法,总结了无损检测技术及其应用现状。综合考虑各种无损检测方法优缺点后对无损检测技术进行了展望。     

Vibration Characteristic of Anchoring System of Bolt and Elastic Wave Propagation Law

Atpresent,theanchoringtechnologyiswidely usedinthefieldofmineraldiggingandrocksoilengi neering,anddevelopsquickly.Thereinforcement techniquesforboltcanreasonablystrengthenrock strengthandloadability,improvethestressstateof rock.Asaresult,itisappliedinthefieldofmining androcksoilengineeringonalargescale.Mean while,thereisanurgentneedforamethodtotest boltbondingquality.Atpresent,acommonlyused methodintheengineeringfieldispulloutexperiment andover coring,whichbelongstodestructivetestal thoughitha…     

Anchoring eccentricity features and rectifying devices for resin grouted bolt/cable bolt

The anchoring eccentricity of the bolt and cable bolt is a common problem in geotechnical support engineering and affects the ability of the bolt and cable bolt to control the rock mass to a certain extent. This paper reports on numerical simulation and laboratory experiments conducted to clarify the effect of eccentricity on the anchoring quality of the bolt and cable bolt, and to establish an effective solution strategy. The results reveal that the anchoring eccentricity causes unbalanced stress distribution and the uncoordinated deformation of the resin layer, which results in higher stress and greater deformation of the resin layer at the near side of the rod body. Additionally, as the degree of anchoring eccentricity increases, the effect becomes more significant, and the resin layer of the anchoring system becomes more likely to undergo preferential failure locally, which weakens the load-bearing performance of the anchoring system. This paper develops an innovative bolt anchoring rectifying device (B-ARD) and cable bolt anchoring rectifying device (C-ARD) on the basis of the structural characteristics of the bolt and cable bolt to better ensure the anchoring effect of them. The working effects of these two devices were verified in detailed experiments and analysis. The experimental results show that the anchoring rectifying devices (ARD) improve and ensure the anchoring concentricity of the bolt and cable bolt, which will help improve the supporting performance of them. The paper provides a convenient and effective method for improving the anchoring concentricity of the bolt and cable bolt, and provides a concept and reference for technical research on improving the effect of roof bolting.     

Stress wave propagation in supporting bolts: A test for bolt support quality

A test method for the non-destructive determination of bolt length, anchoring length, and bolt body force is described. This addresses the problems of low accuracy, limited number of data, and untimely warning signs encountered with existing test methods. Numerical simulations of the bolt, resin, and rock system show that the length accuracy when using the velocity wave is lower than when using the acceleration wave. It is accepted practice to use the acceleration wave for length tests because of improved signal to noise ratios of the waveforms. Laboratory and in situ underground tests showed that the precision of the measurements meets field requirements. Using this method the anchor properties of each single bolt and, thus, the safety of the entire roadway support may be evaluated.     

GFRP锚杆锚固机理试验研究

为了深入研究GFRP锚杆的锚固机理,模拟实际情况制作了试验模型,进行了拉拔试验.通过对实验结果的分析和研究,获得了砂浆粘结GFRP锚杆在拉拔条件下沿杆体的轴力和剪应力分布规律以及随荷载增大的演化过程,对荷载传递的机理进行了讨论,可为同类研究参考.     

Failure mechanism of bolting support and high-strength bolt-grouting technology for deep and soft surrounding rock with high stress

In deep underground mining, the surrounding rocks are very soft with high stress. Their deformation and destruction are serious, and frequent failures occur on the bolt support. The failure mechanism of bolt support is proposed to solve these problems. A calculation theory is established on the bond strength of the interface between the anchoring agent and surrounding rocks. An analysis is made on the influence law of different mechanical parameters of surrounding rocks on the interfacial bond strength. Based on the research, a new high-strength bolt-grouting technology is developed and applied on site. Besides, some helpful engineering suggestions and measures are proposed. The research shows that the serious deformation and failure, and the lower bond strength are the major factors causing frequent failures of bolt support. So, the bolt could not give full play to its supporting potential. It is also shown that as the integrity, strength, interface dilatancy and stress of surrounding rocks are improved, the bond strength will increase. So, the anchoring force on surrounding rocks can be effectively improved by employing an anchoring agent with high sand content, mechanical anchoring means, or grouting reinforcement. The new technology has advantages in a high strength, imposing pre-tightening force, and giving full play to the bolt supporting potential. Hence, it can improve the control effect on surrounding rocks. All these could be helpful references for the design of bolt support in deep underground mines.     

Theoretical analysis of a new segmented anchoring style in weakly cemented soft surrounding rock

According to the tensile failure of rock bolt in weakly cemented soft rock, this paper presents a new segmented anchoring style in order to weaken the cumulative effect of anchoring force associated with the large deformation. Firstly, a segmented mechanical model was established in which free and anchoring section of rock bolt were respectively arranged in different deformation zones. Then, stress and displacement in elastic non-anchoring zone, elastic anchoring zone, elastic sticking zone, softening sticking zone and broken zone were derived respectively based on neural theory and tri-linear strain softening constitutive model of soft rock. Results show that the anchoring effect can be characterized by a supporting parameter b. With its increase, the peak value of tangential stress gradually moves to the roadway wall, and the radial stress significantly increases, which means the decrease of equivalent plastic zone and improvement of confining effect provided by anchorage body. When b increases to 0.72, the equivalent plastic zone disappears, and stresses tend to be the elastic solutions. In addition, the anchoring effect on the displacement of surrounding rock can be quantified by a normalization factor δ.