螺旋锚锚周土体变形试验与抗拔承载力计算模型研究
发布时间：2018-07-31 05:00
【摘要】：螺旋锚作为一种广泛应用于房屋建筑、挡土结构、输电线塔、交通运输等领域的抗拔锚固基础具有施工速度快、环境破坏小、节约建设成本等特点。但由于锚-土相互作用的复杂性,目前对其抗拔机理和性能的理论研究远不能满足工程需要。已有研究主要通过假定破坏面提出了各种计算理论,由于受传统测试手段限制无法获取螺旋锚上拔过程中锚周土体破坏面的精准形状,从而导致很多理论成果在分析锚周土体变形机理时出现了较大的误差,目前螺旋锚的设计主要依赖于工程经验。鉴于传统试验方法的局限性,本文采用非接触式数字图像相关模型试验方法,对螺旋单锚和群锚的上拔过程开展模型试验研究,深入探讨了锚周土体的变形机理：通过对大量变形场试验数据的对比分析,确定了影响单锚抗拔承载力的控制因素,建立了更为符合工程实际情况的螺旋锚多参数抗拔承载力预测模型；通过对群锚模型变形场的研究,提出了不同组合形式下的群锚效应理论及抗拔承载力计算方法,主要工作如下：(1)针对螺旋锚锚周土体变形研究的复杂性,将数字图像测量技术用于锚周土体变形测量,设计了相关试验装置,实现了力加载系统与基于DIC技术的StrainMaster图像采集系统的有效结合。通过对同等试验条件下实测位移与StrainMaster系统得到的位移场进行对比分析,结果表明StrainMaster系统得到的测试结果具有较高的精度,能够实现锚周土体变形过程测量的可视化,从而为实现锚周土体的精确测量提供了技术支持。该方法具有操作简单、实时测量、无干扰、精度高等优点。(2)螺旋单锚上拔过程中锚周土体变化是一个复杂的动态过程,受很多因素影响,并表现为不同的抗拔力学性能。为了分析其抗拔承载力的控制因素,揭示锚周土体的变形破坏机理,分别对不同密实度和不同埋深砂土中螺旋单锚进行了试验研究,系统分析了锚周土体的位移变形规律,得到了不同上拔力阶段下螺旋单锚锚周土体的变形特征。(3)通过对螺旋单锚锚周土体变形场的研究,系统分析了螺旋单锚抗拔破坏的力学机理,基于剪胀理论确定了破坏面形状,提出了单锚临界埋深率和砂土相对密实度之问的关系,根据极限平衡理论构建了能反映浅埋和深埋破坏机理的螺旋单锚抗拔承载力计算模型,并与其他学者的试验研究结果进行了对比分析。结果表明,该计算模型的预测结果与试验结果具有较好的一致性,可实现不同密实度砂土中螺旋单锚抗拔承载力的合理预测。(4)通过对不同密实度砂土中螺旋群锚试验研究,分析了锚周土体变形破坏机理和群锚上拔过程中上拔力-位移关系曲线特征。试验结果表明,群锚抗拔承载力具有明显的叠加效应,且砂土密实度、埋深和锚间距等参数对群锚效应具有显著影响。在此基础上,根据试验成果建立了群锚效应系数与砂土密实度、群锚间距以及埋深率之间的量化关系,为群锚效应计算提供了理论依据。(5)在群锚效应理论分析的基础上,建立了不同组合形式下螺旋群锚效应系数的计算模型。通过对不同工况下群锚效应系数的计算,并与现有试验研究结果的对比分析,该计算模型能够对群锚效应的试验结果进行较好的预测,从而解决了群锚抗拔承载力的计算问题。
[Abstract]:Spiral anchor, widely used in buildings, retaining structure, transmission line tower, transportation and other fields, has the characteristics of fast construction speed, small environmental damage and saving construction cost. However, because of the complexity of the interaction of anchor soil, the theoretical research on its pulling mechanism and performance can not meet the needs of the project at present. The existing research mainly puts forward various calculation theories by assuming the failure surface. Due to the limitation of the traditional testing method, the precise shape of the failure surface of the anchor soil in the uplift process can not be obtained. So a lot of theoretical results have a large error in the analysis of the deformation mechanism of the anchorage soil, and the design of the spiral anchor is mainly based on the design. In view of the limitations of the project, in view of the limitations of the traditional test method, this paper uses a non-contact digital image correlation model test method to carry out a model test study on the spiral single anchor and the uplift process of the group anchor, and deeply discusses the deformation mechanism of the anchor soil. By comparing and analyzing the data of a large number of deformation field tests, the single anchor is determined. The prediction model of multi parameter anti pullout bearing capacity of spiral anchor which is more in line with the actual situation of the project is established. Through the study of the deformation field of the group anchor model, the theory of group anchor effect under different combination forms and the calculation method of uplift bearing capacity are proposed. The main work is as follows: (1) the soil change of the spiral anchor anchors is changed. The digital image measurement technology is applied to the measurement of soil deformation in the anchor soil, and the related experimental device is designed. The effective combination of the force loading system with the StrainMaster image acquisition system based on DIC technology is realized. The displacement field obtained by the measured displacement and the StrainMaster system under the same test conditions is compared and analyzed. The results show that the test results obtained by the StrainMaster system have high accuracy and can realize the visualization of the measurement of the deformation process of the soil anchor soil, thus providing technical support for the accurate measurement of the anchor soil. The method has the advantages of simple operation, real time measurement, no interference and high precision. (2) the anchor cycle in the uplift process of spiral single anchor. Soil change is a complex dynamic process, which is influenced by many factors and shows different pullout mechanical properties. In order to analyze the controlling factors of its uplift bearing capacity, the deformation and failure mechanism of the surrounding soil is revealed, and the spiral single anchors in different compactness and different buried depth sand soil are tested and studied. The anchor soil is systematically analyzed. The deformation characteristics of the displacement and deformation of the body are obtained. (3) through the study of the deformation field of the soil of the spiral single anchor, the mechanical mechanism of the uplift failure of the spiral single anchor is systematically analyzed. Based on the theory of dilatancy, the shape of the failure surface is determined, and the critical depth of the single anchor and the relative density of the sand soil are put forward. The calculation model of the uplift bearing capacity of spiral single anchor which can reflect the mechanism of shallow and deep burial failure is constructed according to the theory of limit equilibrium, and the results are compared with the experimental results of other scholars. The results show that the prediction results of the model are in good agreement with the experimental results, and can realize different compactness. The reasonable prediction of the uplift bearing capacity of the spiral single anchor in the sandy soil. (4) through the study of the spiral group anchors in the sand soil with different density, the deformation and failure mechanism of the soil anchored soil and the relation curve of the uplift displacement relation in the uplift process of the anchors are analyzed. The experimental results show that the uplift bearing capacity of the group anchor has obvious superposition effect and the sand is dense. The parameters such as degree, buried depth and anchor spacing have significant influence on the group anchor effect. On this basis, according to the experimental results, the quantitative relation between the group anchor effect coefficient and the sand density, the spacing of the group anchor and the depth of the buried depth is established. (5) on the basis of the theory analysis of the group anchor effect, the different groups are established. The calculation model of the effect coefficient of the spiral group anchorage under the combined form. Through the calculation of the group anchor effect coefficient under different working conditions and comparing with the existing experimental results, this model can predict the experimental results of the group anchor effect better, thus solving the calculation problem of the anti pullout carrying capacity of the group anchor.
【学位授予单位】：郑州大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TU476
，
本文编号：2154475
[Abstract]:Spiral anchor, widely used in buildings, retaining structure, transmission line tower, transportation and other fields, has the characteristics of fast construction speed, small environmental damage and saving construction cost. However, because of the complexity of the interaction of anchor soil, the theoretical research on its pulling mechanism and performance can not meet the needs of the project at present. The existing research mainly puts forward various calculation theories by assuming the failure surface. Due to the limitation of the traditional testing method, the precise shape of the failure surface of the anchor soil in the uplift process can not be obtained. So a lot of theoretical results have a large error in the analysis of the deformation mechanism of the anchorage soil, and the design of the spiral anchor is mainly based on the design. In view of the limitations of the project, in view of the limitations of the traditional test method, this paper uses a non-contact digital image correlation model test method to carry out a model test study on the spiral single anchor and the uplift process of the group anchor, and deeply discusses the deformation mechanism of the anchor soil. By comparing and analyzing the data of a large number of deformation field tests, the single anchor is determined. The prediction model of multi parameter anti pullout bearing capacity of spiral anchor which is more in line with the actual situation of the project is established. Through the study of the deformation field of the group anchor model, the theory of group anchor effect under different combination forms and the calculation method of uplift bearing capacity are proposed. The main work is as follows: (1) the soil change of the spiral anchor anchors is changed. The digital image measurement technology is applied to the measurement of soil deformation in the anchor soil, and the related experimental device is designed. The effective combination of the force loading system with the StrainMaster image acquisition system based on DIC technology is realized. The displacement field obtained by the measured displacement and the StrainMaster system under the same test conditions is compared and analyzed. The results show that the test results obtained by the StrainMaster system have high accuracy and can realize the visualization of the measurement of the deformation process of the soil anchor soil, thus providing technical support for the accurate measurement of the anchor soil. The method has the advantages of simple operation, real time measurement, no interference and high precision. (2) the anchor cycle in the uplift process of spiral single anchor. Soil change is a complex dynamic process, which is influenced by many factors and shows different pullout mechanical properties. In order to analyze the controlling factors of its uplift bearing capacity, the deformation and failure mechanism of the surrounding soil is revealed, and the spiral single anchors in different compactness and different buried depth sand soil are tested and studied. The anchor soil is systematically analyzed. The deformation characteristics of the displacement and deformation of the body are obtained. (3) through the study of the deformation field of the soil of the spiral single anchor, the mechanical mechanism of the uplift failure of the spiral single anchor is systematically analyzed. Based on the theory of dilatancy, the shape of the failure surface is determined, and the critical depth of the single anchor and the relative density of the sand soil are put forward. The calculation model of the uplift bearing capacity of spiral single anchor which can reflect the mechanism of shallow and deep burial failure is constructed according to the theory of limit equilibrium, and the results are compared with the experimental results of other scholars. The results show that the prediction results of the model are in good agreement with the experimental results, and can realize different compactness. The reasonable prediction of the uplift bearing capacity of the spiral single anchor in the sandy soil. (4) through the study of the spiral group anchors in the sand soil with different density, the deformation and failure mechanism of the soil anchored soil and the relation curve of the uplift displacement relation in the uplift process of the anchors are analyzed. The experimental results show that the uplift bearing capacity of the group anchor has obvious superposition effect and the sand is dense. The parameters such as degree, buried depth and anchor spacing have significant influence on the group anchor effect. On this basis, according to the experimental results, the quantitative relation between the group anchor effect coefficient and the sand density, the spacing of the group anchor and the depth of the buried depth is established. (5) on the basis of the theory analysis of the group anchor effect, the different groups are established. The calculation model of the effect coefficient of the spiral group anchorage under the combined form. Through the calculation of the group anchor effect coefficient under different working conditions and comparing with the existing experimental results, this model can predict the experimental results of the group anchor effect better, thus solving the calculation problem of the anti pullout carrying capacity of the group anchor.
【学位授予单位】：郑州大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TU476
，
本文编号：2154475
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