建筑基桩刚度测定方法及试验验证
发布时间：2018-10-12 13:17
【摘要】：基础以刚度形式向建筑物提供支撑能力,要想了解桩基础施工后的支撑能力,就要对基桩的刚度进行测定,因此测定基桩刚度就成为了确定基桩承载力的核心问题。《建筑基桩检测技术规范》(JGJ106-2003)的条文说明中关于刚度的计算公式Kd=(2πfM)/|V/F|m来获得弹簧刚度值,公式的实质就是将桩视为刚性体即质-弹系统的振动试验。规范分析揭示了公式Kd=(2πfM)/|V/F|m的理论基础、公式来源和应用中的相关问题,由于桩土系统的振动试验需要相对比较大的激励力,而实际工程中桩的固有振动频率基本在60赫兹以下,试验设备需要具有良好的低频特性,因此它在工程应用方面目前可能会有一些困难需要克服。 针对建筑基桩的刚度测量问题进行了试验设计,制作了钢筋混凝土桩,并将试验桩置于弹簧上,以弹簧刚度替代土对桩的支撑刚度,分别用静态和动态方法对弹簧的刚度进行测定。本文研究的主要内容如下： 1.静态加载试验方法,对弹簧加静载荷的方法测量得到的刚度值,对应于用《建筑基桩检测技术规范》(JGJ106-2003)单桩竖向抗压静载试验所得Q-s曲线的初始段切线的斜率。 2.将桩视为弹性体的动态试验方法：将弹簧和一个混凝土桩组成的系统进行波动试验,即使用《建筑基桩检测技术规范》(JGJ106-2003)给出的机械阻抗方法,获取桩顶面的速度导纳曲线,曲线反映将桩体视为弹性体的动态性能,根据导纳曲线提供的数据,用公式K=(2π△f0)2/2×f×(?)P×Q来获得弹簧刚度值。将静态试验方法得到的弹簧刚度值作为基准,将动态试验方法得到的弹簧刚度值与之作比较,速度导纳曲线是对系统动力学性能的深刻而全面的描述,用它所提供的相关数据来计算的刚度值理应与前者相同,试验完全证明了这一点。 通过试验表明当应用《建筑基桩检测技术规范》(JGJ106-2003)给出的机械阻抗方法,将刚度公式改用K=(2π△f0)2/2×f×(?)P×Q来计算基桩刚度,可以解决基桩承载力测定问题,实现用低应变方法测定基桩承载力。
[Abstract]:The foundation provides support capacity to the building in the form of stiffness. In order to understand the supporting capacity of the pile foundation after construction, it is necessary to measure the stiffness of the foundation pile. Therefore, the determination of pile stiffness becomes the core problem in determining the bearing capacity of foundation pile. The stiffness calculation formula Kd= (2 蟺 fM) / V / F / m in JGJ106-2003 (Building pile testing Technical Code) is used to obtain the spring stiffness value. The essence of the formula is to treat the pile as a rigid body, that is, the vibration test of the mass-elastic system. The normative analysis reveals the theoretical basis of the formula Kd= (2 蟺 fM) / V / F / m, the source of the formula and the related problems in its application. Because the vibration test of pile-soil system requires relatively large excitation force, the natural vibration frequency of the pile in practical engineering is basically below 60 hertz. The test equipment needs to have good low frequency characteristic, so it may have some difficulties to overcome in engineering application at present. Based on the experimental design of the stiffness measurement of the building foundation pile, the reinforced concrete pile is made, and the test pile is placed on the spring to replace the soil supporting stiffness of the pile. The stiffness of spring was measured by static and dynamic methods. The main contents of this paper are as follows: 1. The stiffness measured by the method of spring loading and static loading corresponds to the slope of the initial section tangent of Q-s curve obtained from the vertical compression static load test of single pile (JGJ106-2003). Dynamic test method of treating pile as elastic body: the system composed of spring and concrete pile is subjected to wave test, even by using the mechanical impedance method given by JGJ106-2003, the velocity admittance curve of pile top surface is obtained. The curve reflects the dynamic behavior of the pile as an elastic body. According to the data provided by the admittance curve, the spring stiffness is obtained by using the formula K = (2 蟺 f 0) 2 / 2 脳 f 脳 P 脳 Q. The spring stiffness obtained by the static test method is taken as the reference, and the spring stiffness obtained by the dynamic test method is compared with it. The velocity admittance curve is a profound and comprehensive description of the dynamic performance of the system. The stiffness calculated with the relevant data is supposed to be the same as that of the former, which is proved by experiments. The test results show that when the mechanical impedance method given by JGJ106-2003 is used, the stiffness formula can be changed to K = (2 蟺 f 0) 2 / 2 脳 f 脳 (?) P 脳 Q to calculate the stiffness of foundation pile, which can solve the problem of pile bearing capacity measurement. The bearing capacity of foundation pile can be measured by low strain method.
【学位授予单位】：内蒙古工业大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU473.16
本文编号：2266268
[Abstract]:The foundation provides support capacity to the building in the form of stiffness. In order to understand the supporting capacity of the pile foundation after construction, it is necessary to measure the stiffness of the foundation pile. Therefore, the determination of pile stiffness becomes the core problem in determining the bearing capacity of foundation pile. The stiffness calculation formula Kd= (2 蟺 fM) / V / F / m in JGJ106-2003 (Building pile testing Technical Code) is used to obtain the spring stiffness value. The essence of the formula is to treat the pile as a rigid body, that is, the vibration test of the mass-elastic system. The normative analysis reveals the theoretical basis of the formula Kd= (2 蟺 fM) / V / F / m, the source of the formula and the related problems in its application. Because the vibration test of pile-soil system requires relatively large excitation force, the natural vibration frequency of the pile in practical engineering is basically below 60 hertz. The test equipment needs to have good low frequency characteristic, so it may have some difficulties to overcome in engineering application at present. Based on the experimental design of the stiffness measurement of the building foundation pile, the reinforced concrete pile is made, and the test pile is placed on the spring to replace the soil supporting stiffness of the pile. The stiffness of spring was measured by static and dynamic methods. The main contents of this paper are as follows: 1. The stiffness measured by the method of spring loading and static loading corresponds to the slope of the initial section tangent of Q-s curve obtained from the vertical compression static load test of single pile (JGJ106-2003). Dynamic test method of treating pile as elastic body: the system composed of spring and concrete pile is subjected to wave test, even by using the mechanical impedance method given by JGJ106-2003, the velocity admittance curve of pile top surface is obtained. The curve reflects the dynamic behavior of the pile as an elastic body. According to the data provided by the admittance curve, the spring stiffness is obtained by using the formula K = (2 蟺 f 0) 2 / 2 脳 f 脳 P 脳 Q. The spring stiffness obtained by the static test method is taken as the reference, and the spring stiffness obtained by the dynamic test method is compared with it. The velocity admittance curve is a profound and comprehensive description of the dynamic performance of the system. The stiffness calculated with the relevant data is supposed to be the same as that of the former, which is proved by experiments. The test results show that when the mechanical impedance method given by JGJ106-2003 is used, the stiffness formula can be changed to K = (2 蟺 f 0) 2 / 2 脳 f 脳 (?) P 脳 Q to calculate the stiffness of foundation pile, which can solve the problem of pile bearing capacity measurement. The bearing capacity of foundation pile can be measured by low strain method.
【学位授予单位】：内蒙古工业大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU473.16
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