渗压计在渗流监测中的误差分析及对策
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摘要
为研究渗压计在渗流监测中的精度,并分析产生误差的原因,对某土石坝埋设于测压管中的30余支渗压计进行了比测。比测方法为:分别采用平尺水位计和自动化采集装置同时进行人工直接测读和机器自动测读。结果表明,比测误差一般在-0.5～0.3 m之间,超过渗压计标称精度约10倍之多,且误差分布呈随机跳动的特征。为进一步分析误差来源,对部分测压管管口装置开孔后进行了比测,并实施了密封容器内的渗压计数据采集试验,结果证明,渗压计误差主要来源于环境大气压及管内局部气压的变化。在此基础上,提出了减小渗压计误差的技术措施,包括使用通气型渗压计、管口增设通气孔、进行气压改正等。
To research the precision of osmometer in seepage monitoring,and analyze the cause of errors,more than 30 osmometers were installed in a rock-earth dam and the measurement and comparison were conducted.The water table was recorded by manual tape gauge and automatic instrument simultaneously.The result indicates that measured water table error is between-0.5m to 0.3m,which is 10 times larger than osmometer′s nominal precision and the errors distribute randomly.To make a further study on error sources,we drilled ventilation holes on partial tube lids for measurement comparison,and acquired osmometer's data in a sealed tank.It is proved that the errors are mainly caused by variation of atmospheric pressure and internal air pressure in the tube.Based on the analysis,we present technical method to minimize the measurement error of osmometer,including air-ventilated osmometer,drilling ventilation hole on the tube lid,and atmosphere pressure correction.
To research the precision of osmometer in seepage monitoring,and analyze the cause of errors,more than 30 osmometers were installed in a rock-earth dam and the measurement and comparison were conducted.The water table was recorded by manual tape gauge and automatic instrument simultaneously.The result indicates that measured water table error is between-0.5m to 0.3m,which is 10 times larger than osmometer′s nominal precision and the errors distribute randomly.To make a further study on error sources,we drilled ventilation holes on partial tube lids for measurement comparison,and acquired osmometer's data in a sealed tank.It is proved that the errors are mainly caused by variation of atmospheric pressure and internal air pressure in the tube.Based on the analysis,we present technical method to minimize the measurement error of osmometer,including air-ventilated osmometer,drilling ventilation hole on the tube lid,and atmosphere pressure correction.
引文
[1]康强,张小洁,季中托,等.环境大气压的变化规律与差压式真空度测量的系统误差[J].真空,2004,41(4):71-73.
[2]李志安,李永生,胡辉译.地球自转的变化[M].北京:地震出版社,1988.
[3]佘守宪.范氏方程、玻意耳温度与理想气体状态方程的偏差[J].物理通报,2003,(10):4-7.
[2]李志安,李永生,胡辉译.地球自转的变化[M].北京:地震出版社,1988.
[3]佘守宪.范氏方程、玻意耳温度与理想气体状态方程的偏差[J].物理通报,2003,(10):4-7.
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