| 泥石流浆体与大颗粒冲击力特征的试验研究 |
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| 引用本文： | 曾 超,苏志满,雷 雨,余 健.泥石流浆体与大颗粒冲击力特征的试验研究[J].岩土力学,2015,36(7):1923-1930. |
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| 作者姓名： | 曾 超 苏志满 雷 雨 余 健 |
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| 作者单位： | 1. 中国科学院水利部成都山地灾害与环境研究所 中国科学院山地灾害与地表过程重点实验室，四川 成都 610041； 2. 国家测绘地理信息局四川基础地理信息中心 四川省应急测绘与防灾减灾工程技术研究中心，四川 成都 610041； 3. 成都理工大学 地质灾害防治与地质环境保护国家重点实验室，四川 成都610059 |
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| 基金项目： | 中国科学院重点部署项目(No. KZZD-EW-05-01-03)；四川省科技计划项目(No. 2014SZ0163)；四川省测绘地理信息局局科技支撑项目 (No. J2014ZC11)；四川省地理国情监测工程技术研究中心资助项目(No. GC201503)。 |
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| 摘 要： | 开展了密度为1 400～2 200 kg/m3的泥石流浆体、浆体与大颗粒混合流体的冲击力试验，获取了流速为2.8～4.9 m/s条件下31组冲击力试验数据。采用小波分析方法有效地去除了冲击力数据中的噪声信号，依据离散傅里叶变换（FFT）为基础的频谱分析结果，将低频泥石流浆体冲击和高频大颗粒冲击的临界频率值界定为2 Hz，实现了浆体和大颗粒冲击信号的分离。目前水动力学公式中待定系数α缺乏统一的确定方法，以不同地区157组泥石流观测和试验数据为基础，建立了待定系数?与流体Fr数的幂函数关系，形成可表征不同流态，且弱化尺度效应的浆体动压力计算公式。与泥石流浆体平滑信号相比，大颗粒冲击压力具有一定随机性。泥石流大颗粒冲击次数与频率随大颗粒的质量比增加而增大，其质量比从0.05增至0.21时，冲击总次数从1 305次增至2 838次，冲击频率从82次/s增至195次/s，且龙头段大颗粒的冲击频率高于后续泥石流体。测得大颗粒的压力约为60 kPa，是相同密度和流速下浆体动压力的3倍。随着大颗粒比例的增加，上部1#和2#传感器测得大颗粒冲击频率增加量明显高于下部3#～6#。说明随着流体中大颗粒比例上升，颗粒物质多集中于泥石流上部或表层运动，也佐证了泥石流运动中大颗粒多集中在龙头顶部的认识。对大颗粒和浆体冲击规律的分析可为固液两相流运动机制研究和防治工程设计以及承灾体易损性定量评估提供合理参数。
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| 关 键 词： | 泥石流 固液两相流 浆体 大颗粒 冲击力 |
| 收稿时间： | 2014-02-11 |
An experimental study of the characteristics of impact forces between debris flow slurry and large-sized particles |
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| ZENG Chao,SU Zhi-man,LEI Yu,YU Jian.An experimental study of the characteristics of impact forces between debris flow slurry and large-sized particles[J].Rock and Soil Mechanics,2015,36(7):1923-1930. |
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| Authors: | ZENG Chao SU Zhi-man LEI Yu YU Jian |
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| Abstract: | A series of impact experiments were conducted on debris flow slurries and the mixtures of the debris flow slurry and large-sized particles with densities of 1 400-2 200 kg/m3, and 31 groups of impact experimental data at velocities of 2.4-5.2 m/s were obtained. The noise signals generated from device vibration and environmental interference are filtered out with the wavelet analysis method. Based on the results of the frequency spectral analysis using the fast Fourier transform method, a frequency threshold of 2 Hz is identified so that the low-frequency slurry impact force and the high-frequency large-sized particle impact force can be effectively separated. In the current hydrodynamic model the empirical coefficient α is generally difficult to determine. To resolve the issue, the functional dependence of the fluid Froude number Fr on coefficient α is developed based on 157 sets of debris flow monitoring data; and a formulation for calculating the slurry impact force is proposed, which represents different flow forms and the diminishing size effect. Compared to the smooth nature of slurry impact force, the large-sized particle impact force has more random characteristics. Both the number and frequency of particles impact on sensors increase when more particles are mixed in the flow. When mass ratio of particles increases from 0.05 to 0.21, the impact number increases from 1 305 to 2 838 times, and the impact frequency also increases from 82 to 195 times per second. The average particle impact force is about 60 kPa, which is about 3 times that of slurry. The frequency of particles detected by the upper sensors becomes larger than that detected by the bottom sensors as the particles content increases, demonstrating that the particles are prone to concentrate on the surface or at the head of debris. |
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| Keywords: | debris flow solid-liquid two phase flow slurry large-sized particles impact force |
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