考虑温度效应的静力水准仪测试精度修正模型

Modified model for the temperature effect-induced error in the hydrostatic leveling system

为系统研究温度效应对静力水准测试系统(HLS)测试精度的影响,降低HLS测试误差。结合笔者前期已完成的环境温度研究,搭建了温度梯度试验平台,开展了系列不同温度梯度条件下HLS测试精度试验研究,对升/降温模式、温度梯度TG变化量、冷媒膨胀系数γ_(di)和联通管系数γ_(pi)、测点间距D_(test)的影响程度进行了定量化研究。结果表明:升温或降温模式的温度梯度影响系数ΔP_(t-G)仅差0.003 mm/℃,升/降温模式对HLS测试精度没有显著影响;测点高程与TG具有明显相关性;ΔP_(t-G)与(γ_(di)-γ_(pi))呈线相关性,且ΔP_(t-G)与D_(test)存在幂函数关系。以此建立了HLS温度效应修正模型,并在南京长江隧道和太湖隧道的沉降监测中验证了模型的可靠性和适用性。

To investigate the influence of temperature effect on the measurement accuracy of hydrostatic leveling system(HLS)and reduce the measurement error,a temperature gradient test platform is established,which combines with the ambient temperature research completed in the previous stage.Researches are conducted on the HLS measurement accuracy under temperature gradient conditions,and the heating/cooling mode,temperature gradient TG variation,liquid expansion coefficientγ_(di)and communicating pipe expansion coefficientγ_(pi),and measuring-point distance D_(test)are analyzed quantitatively.Results show that the temperature gradient influence coefficientΔP_(t-G)between the heating and cooling mode is only 0.003 mm/℃,which indicates the limited effect of the heating/cooling mode on the HLS measurement accuracy.The elevation of the measuring point has an obvious correlation with TG.TheΔP_(t-G)has a linear correlation with the(γ_(di)-γ_(pi))and also shows the power function relationship with D_(test).Finally,a modified model for the temperature effect-induced error in HLS is formulated.The reliability and applicability of the model are evaluated by the settlement tests of the Nanjing Yangtze River tunnel and Taihu tunnel.