锚索有效锚固长度及其对粘结强度取值影响研究

发布时间：2018-04-12 17:05

本文选题：石灰岩 + 有效锚固长度　；参考：《湖南大学》2015年硕士论文

【摘要】：锚索锚固技术因其具有经济适用、安全可靠以及便捷施工等优点,而被广泛应用,且国内外学者已经对其展开了广泛而深入的研究,然而由于锚固地层的多变性、锚固结构的变异性,锚固方式的多样性,现有研究成果在面对特定工程问题时仍显不足。本文针对长沙大王山冰雪世界坑壁支护项目中石灰岩地区应用大吨位预应力锚索的注浆体与地层粘结强度取值问题,完成了锚索拉拔试验,并对锚索有效锚固长度测试、分析,以及锚固注浆体与地层粘结强度取值方法的进行深入的研究,主要完成了以下工作:(1)在对现有锚杆(索)锚固体应力应变测试技术进行的研究和分析的基础上,探索了采用混凝土应变计进行锚索有效锚固长度测试的方法。通过建立数值模型,模拟了锚索的拉拔过程,分析了荷载从钢绞线到注浆体再到锚固层的传递过程中锚固体的受力变形的特性,据此提出了应变计设置的最佳位置。(2)依托工程锚索自由段长度达50m,锚固地层为石灰岩岩层的特点,研究了P-S曲线反演锚固界面参数的适用性。针对P-S曲线反演锚固界面参数这一方法,根据荷载传递法,推导了荷载位移关系理论模型,然后考虑杆体材料弹性模量的变异性,分析了评价自由段长度对于锚固体顶部位移计算结果影响的方法。并基于既有实例,分别研究了P-S曲线反演锚固界面参数对不同自由段长度、土层锚杆和岩层锚杆的适用性。(3)针对P-S曲线反演锚固界面参数不适用于岩层锚杆的问题,基于荷载变形基于注浆体向地层传递荷载的双折线荷载传递模型的力学机制,对锚杆荷载由注浆体向地层荷载传递的全过程进行了分析,研究了锚固段长度对粘结强度取值影响的机理。在导得锚固体极限状态下位移解答的基础上,建立了根据一种根据锚杆拉拔试验得到的极限荷载与残余荷载结果来计算不同锚固段长度对注浆体与地层粘结强度影响系数的方法。(4)设计并完成了石灰岩地层区大吨位预应力锚索拉拔试验,对采用混凝土应变计测试锚固长度的方法进行了初试,并将研究得到的不同锚固段长度对注浆体与地层粘结强度影响系数的计算方法应用到依托工程,得到依托工程所需要的不同锚固段长度粘结强度值。
[Abstract]:Anchor cable anchoring technology has been widely used because of its advantages of economic applicability, safety, reliability and convenient construction, and has been extensively and deeply studied by domestic and foreign scholars. However, because of the variability of anchoring strata,The variation of Anchorage structure and the diversity of anchoring methods are still insufficient in the face of specific engineering problems.As well as the deep research on the method of determining the bond strength between the anchor grouting body and the stratum, the following work has been accomplished: 1) on the basis of the research and analysis of the existing stress and strain testing technology of the anchor body (cable),The test method of effective anchoring length of anchor cable with concrete strain gauge is explored.By establishing a numerical model, the drawing process of the anchor cable is simulated, and the mechanical deformation characteristics of the anchor body during the transmission process of the load from the steel strand to the grouting body to the anchor layer are analyzed.Based on this, the optimum position of strain gauge is put forward. The length of anchoring cable free section is up to 50m, and the anchoring strata are limestone strata. The applicability of P-S curve inversion of Anchorage interface parameters is studied.According to the method of P-S curve inversion of Anchorage interface parameters, a theoretical model of load-displacement relation is derived according to the load-transfer method, and then the variability of elastic modulus of rod material is considered.The method of evaluating the effect of the length of free section on the calculation results of Anchorage top displacement is analyzed.Based on the existing examples, the applicability of P-S curve inversion of anchoring interface parameters to different length of free section, soil layer anchor rod and rock layer anchor rod is studied respectively. In view of the problem that P-S curve inversion anchoring interface parameter is not suitable for rock layer anchor rod.Based on the mechanical mechanism of the double line load transfer model based on the transfer of load from the grouting body to the stratum, the whole process of the load transfer from the grouting body to the stratum is analyzed.The influence of anchoring length on bond strength is studied.On the basis of the displacement solution under the ultimate state of anchoring body,Based on the limit load and residual load of anchor rod drawing test, a method of calculating the influence coefficient of different anchoring length on bond strength between grouting body and stratum is established. 4) the limestone stratum area is designed and completed.Large tonnage prestressed anchor cable drawing test,The method of testing anchoring length with concrete strain gauge is first tested, and the method of calculating the influence of different length of anchoring section on bond strength between grouting body and stratum is applied to supporting engineering.The bond strength of different anchoring section length is obtained.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU476

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