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王永志, 杨阳, 徐光明, 汤兆光, 张雪东, 孙锐. 土工离心模型试验软接触式微型土压计研制及性能评价[J]. 岩土工程学报. DOI: 10.11779/CJGE20230642
引用本文: 王永志, 杨阳, 徐光明, 汤兆光, 张雪东, 孙锐. 土工离心模型试验软接触式微型土压计研制及性能评价[J]. 岩土工程学报. DOI: 10.11779/CJGE20230642
Development and performance evaluation of a novel soft-contact earth pressure transducer for geotechnical centrifuge modeling[J]. Chinese Journal of Geotechnical Engineering. DOI: 10.11779/CJGE20230642
Citation: Development and performance evaluation of a novel soft-contact earth pressure transducer for geotechnical centrifuge modeling[J]. Chinese Journal of Geotechnical Engineering. DOI: 10.11779/CJGE20230642

土工离心模型试验软接触式微型土压计研制及性能评价

Development and performance evaluation of a novel soft-contact earth pressure transducer for geotechnical centrifuge modeling

  • 摘要: 微型土压计是土工离心模型试验的重要测量技术之一。为解决刚性土压计测量中拱效应、尺寸效应、厚径比等经典误差问题及提升频响速率和精度,尝试开发了一种全新软接触式微型土压计ESP-II,介绍了其技术创新和设计方法。以两种国际代表性土压计为参考,设计开展一系列离心模型试验,对其感应精度、速率和适用性进行评价。主要结论:1)逐级加载离心加速度5~50g试验下,各深度ESP-II和两种参考传感器测试结果与理论值差异较小,平均误差分别为5.16%、6.70%和4.85%,三者沿深度拟合K0优度系数R2均≥0.9893;2)脉冲荷载试验中ESP-II最大响应时间约7.8ms,略优于两种参考传感器,具有良好的频响速率。3)不同幅值正弦、地震等动荷载试验下,三种传感器测得土压力均呈一致增量趋势, K0约由0.43~0.45增至0.51~0.56,与既有规律认识吻合。4)离心机下降卸荷过程中,ESP-II测得时程表现良好连续性和光滑性,反映软接触式设计有利于保障土体与传感器良好接触和稳定响应。研究成果,初步证明了软接触式土压计适应于静、动力离心试验需求,具有重要价值与应用前景。

     

    Abstract: The miniature earth pressure transducer is one of the key testing tools in geotechnical centrifuge modeling. Aiming at solving the classical error problems such as arching effect, size effect and thickness-diameter ratio in the measurement of rigid transducer, improving the frequency response rate and induction accuracy, a novel soft-contact transducer ESP-II was developed, and its innovations and design methods were introduced. Taking two internationally representative earth pressure transducers as reference, a series of centrifuge model tests were designed and carried out to evaluate its accuracy, frequency response and applicability. The main conclusions are as follows: 1) In the static centrifugal acceleration test spinning up from 5g to 50g, the difference between the theoretical values and the test results of ESP-II and the two reference transducers at each depth is small, and the average deviations are 5.16%, 6.70% and 4.85%, the coefficient R2 of the three curves K0 which fitting along the depth is ≥ 0.9893. 2) In the pulse load test, the maximum response time of ESP-II is about 7.8ms, which is slightly better than the two reference transducers and has a satisfactory frequency response. 3) In the dynamic load tests of sine and seismic with different amplitudes, the incremental trend of earth pressure measured by the three transducers is basically consistent. The variation range of K0 increases from 0.43~0.45 before the seismic to 0.51~0.56 after the seismic, which is consistent with the existing theory. 4) In the deceleration stage of the centrifuge, the good continuity and smoothness of the time history measured by the ESP-II, which reflects the soft-contact design is conducive to ensure good contact and stable response between the soil and the transducer. The research results have preliminarily proved that the developed soft-contact transducer satisfies the requirements of static and dynamic centrifugal test, ESP-II has significant application value and immense potential.

     

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