Development of In-situ Testing Equipment for Friction Between Ground and Structure Foundation

地基与结构地基摩擦力现场测试设备的研制

• 批准号: 62850104
• 负责人: KISHIDA Hideaki
• 金额: $ 3.52万
• 依托单位: Tokyo Institute of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Developmental Scientific Research
• 财政年份: 1987
• 资助国家: 日本
• 起止时间: 1987 至 1988
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-62850104/
• 关键词: Pile; Earth Anchor; Soil; Foundation; Friction; 原位置試験

In the present design of piles and earth anchors, the estimation of frictional resistance is dependent on the loading test and/or empiricism with a considerable uncertainty. For better understanding and estimation of frictional resistance, a testing apparatus is developed for the measurement of in-situ friction and normal stress.1. Studies on friction between soils and construction materials are reviewed. These studies often use the frictional resistance as the ratio of the shear stress to the normal stress acting on the interface. It is necessary to estimate the normal stress for appropriate use of the results of these studies.2. Experimental studies on the in-situ tests are reviewed. Most apparatus developed in the experimental studies are either to measure the in-situ lateral stress or frictional resistance between ground and the apparatus. It is rare to measure both lateral stress and frictional resistance with one apparatus. The theoretical studies have not yet succeeded to evaluate the accurate lateral stress acting on installed pile surface.3. A new apparatus is designed and fabricated to measure both frictional resistance and lateral stress at the same time. The design was based on the piezo-cone penetrometer which measure tip resistance, local side friction and pore water pressure at the same time. One part of the friction sleeve was machined from the inside to a wall thickness of some 0.3mm. The bending strain was mesured by means of electric resistance strain gauges bonded to the inside of the thin part of the friction sleeve. The measured values were calibrated under the compressive load and hydraulic pressure.4. Laboratory tests were carried out in large sand samples with controlled density under imposed boundary (lateral and overburden) pressure. The test results showed that the new apparatus is capable of measuring the lateral and frictional resistance at the same time.

在目前的桩和土锚设计中，摩擦阻力的估计依赖于加载试验和/或经验，具有相当大的不确定性。为了更好地理解和估计摩擦阻力，开发了一种用于测量原位摩擦和法向应力的测试装置。综述了土与建筑材料摩擦的研究进展。这些研究通常使用摩擦阻力作为作用在界面上的剪切应力与正应力的比值。为了适当地利用这些研究结果，有必要估计正常应力。对原位试验的实验研究进行了综述。在实验研究中研制的仪器大多是测量地应力或地面与仪器之间的摩擦阻力。用一台仪器同时测量侧向应力和摩擦阻力是很少见的。理论研究尚未成功地准确计算作用在已安装桩表面的侧向应力。设计并制作了一种同时测量摩擦阻力和侧向应力的装置。该设计基于同时测量尖端阻力、局部侧摩擦和孔隙水压力的压电锥贯入仪。摩擦套的一部分从内部加工到壁厚约0.3mm。弯曲应变是通过粘接在摩擦套薄部分内部的电阻应变片来测量的。在压缩载荷和液压作用下对测量值进行了标定。在施加的边界（侧向和覆盖层）压力下，在控制密度的大型砂样中进行了实验室测试。试验结果表明，该装置能够同时测量侧向阻力和摩擦阻力。

项目成果

上杉守道・ほか: 第24回土質工学研究発表会 発表講演集. (1989)

Morimichi Uesugi 等：第 24 届土壤工程研究会议演讲集（1989 年）。

上杉守道 他: 第24回土質工学研究発表会 発表講演集. (1989)

Morimichi Uesugi 等：第 24 届土壤工程研究会议演讲集（1989 年）。

Uesugi, M.: "An experience with an In-situ Lateral Stress Sensing Cone" Proc. of the 24th Japan National conference on Soil Mechanics and Foundation Engineering. (1989)

Uesugi, M.：“原位横向应力传感锥的体验”Proc。