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岩土压力传感器匹配误差的计算 总被引:9,自引:2,他引:9
对岩土压力传感器的匹配误差,从解析理论研究出发,提出两次压陷等假定条件,推导出在3种使用场合时的匹配误差计算公式,得出匹配误差计算公式中有关参数的确定方法或具体量值,给出了实用的匹配误差定量计算公式。 相似文献
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本文简要地评估了土力学现场测量中常用的连杆式应变传感器的力学匹配误差。对一种特殊的,匹配误差小的非接触互感式传感器的特性作出分析。设计了与这种传感器配用的,适合于动、静态测量的土壤应变仪,给出了它的主要性能指标。 相似文献
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在介绍了岩土压力传感器匹配误差概念的基础上,论述了匹配误差的稳定性、等效性、真实性和实用性以及各特性之间的相关性。通过研究得出:匹配误差特性的核心是稳定性;传感器刚性饼状设计是保证稳定性的必要条件;等效匹配误差不一定是真实的,但即使是不真实,也不影响实用性。 相似文献
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为掌握离心力场环境下微型土压力传感器与土介质相互作用引起的匹配误差特性,结合匹配误差理论,通过液体标定试验和离心力场中土介质标定试验,讨论了微型土压力传感器在模量相对较大土介质中的非线性响应特征及其主要影响因素。试验分析表明:在液压条件下微型土压力传感器具有良好的线性响应特性;在离心力场环境中微型土压力传感器表现出的显著非线性响应特性是由加载过程中土介质模量的改变引起;基于建立的匹配误差随土介质模量变化的关系曲线对测试数据进行非线性修正,可明显提高微型土压力传感器在模量相对较大土介质中的测试精度。 相似文献
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为掌握土压力传感器置于硬土介质中呈现的非线性响应特性,建立了传感器与土介质的相互作用模型,运用有限元分析了满足匹配误差稳定所需的传感器与土介质的模量比条件。进行了传感器的单体标定和级配碎石土介质标定试验,探讨了传感器非线性响应的主要影响因素。计算与试验表明,目前国内主流的双膜土压力传感器在量测硬土介质中的土压力时,由于模量偏小标定曲线非线性显著;土压力传感器单体标定曲线线性度较高且其模量基本稳定,表明土介质的模量变化是引起标定曲线非线性的主要因素;通过将传感器置于与使用环境相近的土介质中进行标定,并采用非线性修正可明显提高硬土介质中土压力量测的准确性。 相似文献
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研制了一款基于PNI磁感式传感器和SCAl00T加速度传感器的矿用全空间钻孔测斜仪。详细论述了系统的总体结构、测量原理及传感器的电路设计;同时分析了系统的误差及其来源,给出了误差补偿模型及其补偿、标定的方法。实验结果表明:该钻孔测斜仪具有体积小、精度高、可靠性高等特点,满足工程的需要。 相似文献
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海洋水色卫星遥感研究与进展 总被引:7,自引:3,他引:7
系统介绍了目前海洋水色卫星遥感在海洋碳通量、生物海洋学及上层海洋过程研究,以及海岸带环境监测与管理中的主要应用方向;分析了上述应用对水色卫星传感器在时空分辨率、光谱波段设置和空间覆盖范围等方面的具体设计要求;概括了新一代水色卫星传感器的特点;指出了水色卫星遥感资料应用中的定标、大气校正及定量反演技术等关键问题;介绍了各国海洋水色卫星遥感的发展计划,提出了我国海洋水色卫星遥感研究的对策。 相似文献
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盾构隧道施工中采用了特殊的工艺——壁后注浆,包裹了隧道表面预埋设的土压力计,壁后注浆对土压力计的包裹将影响其监测结果的可靠性。在注浆体力学试验基础上,建立能考虑注浆体固结硬化过程的有限元模型,探讨注浆体层的包裹对土压力计监测结果的影响。注浆体注入盾尾空隙后,终凝前处于流动状态,具有较强调节土压力计部位局部土体不均匀沉降和畸变应力场的能力,监测土压力与实际较为接近,其匹配误差远小于通常地下结构表面监测土压力的匹配误差。 相似文献
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孔隙水压力传感器动态特性模型,设计与试验 总被引:2,自引:0,他引:2
本文对动态孔隙水压力传感器的设计问题进行了专门研究。内容包括:(a)根据泊稷叶公式建立了滤水系统的动态特性模型;(b)由该模型对典型被测压力信号的响应误差提出了设计判据;(c)孔隙水压力传感器的设计与制作;(d)在激波压力作用下,模型的理论响应与传感器的实测响应作了检验对比。此外,还简单介绍了传感器在现场的应用情况。 相似文献
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岩溶塌陷临界土洞高度的确定--以唐山市体育场岩溶塌陷为例 总被引:1,自引:3,他引:1
土洞的产生和发展是岩溶塌陷的基础和前提,临界土洞是土洞发展的最终阶段,以临界土洞为界,岩溶塌陷在时间和空间上划分为内部塌陷阶段和地表塌陷阶段。内部塌陷阶段是土洞在覆盖层土体内部的发育扩展阶段,土洞顶板土体的破坏形式类似于地下洞室洞顶围岩的破坏。根据地下洞室普氏平衡拱理论,建立覆盖层土体的天然平衡拱高度,即临界土洞高度公式,并以唐山市体育场岩溶塌陷为例,对该公式进行验证评价,计算所得塌陷的临界土洞高度与实际情况相符合,误差仅为4.3%。 相似文献
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G. R. Adhikari A. I. Theresraj R. N. Gupta 《Fragblast: International Journal for Blasting and Fragmentation》2005,9(2):79-92
Various methods of transducer mounting provide varying degrees of coupling between the transducer and the measurement surface. The influence of four of these methods on vibration measurements was studied. For this purpose, the first transducer was placed freely on a horizontal surface, the second one was 'sandbagged', the third one was 'spiked' and the fourth one was completely buried in soil. These transducers were mounted side by side and ground vibrations were monitored for 14 blasts at an opencast coal mine.
Ground vibrations in terms of peak particle velocity, peak vector sum and frequency with different mounting methods were analysed. Assuming the data of the buried transducer as the most acceptable one, relative values of other transducers were determined and plotted. For the given tolerance for instrumental and human errors, anomalous readings were found in some cases. The waveforms of the buried transducer were then compared with those of others. Clear distortion in the waveforms or a very low correlation coefficient between two waveforms was suspected poor coupling.
The results indicate that decoupling is most likely with the surface transducer. However, the sandbagged and spiked transducers are also prone to decoupling. Decoupling can result in higher or lower ground vibration. Therefore, burial should be the preferred method for mounting of transducers in soil. 相似文献
Ground vibrations in terms of peak particle velocity, peak vector sum and frequency with different mounting methods were analysed. Assuming the data of the buried transducer as the most acceptable one, relative values of other transducers were determined and plotted. For the given tolerance for instrumental and human errors, anomalous readings were found in some cases. The waveforms of the buried transducer were then compared with those of others. Clear distortion in the waveforms or a very low correlation coefficient between two waveforms was suspected poor coupling.
The results indicate that decoupling is most likely with the surface transducer. However, the sandbagged and spiked transducers are also prone to decoupling. Decoupling can result in higher or lower ground vibration. Therefore, burial should be the preferred method for mounting of transducers in soil. 相似文献
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利用1998年7月6日至8月9日青藏高原GAME-Tibet试验区MS3608站点的4cm、20cm和100cm的土壤水分观测数据同化SiB2模型输出的表层、根区和深层土壤水分,探讨了一个基于集合卡尔曼滤波和简单生物圈模型的单点土壤水分同化方案。分析和评价了集合大小、同化周期、模型误差、背景场误差以及观测误差对同化系统性能的影响。结果表明:①增加集合数目可以减小土壤水分同化系统的误差,但同时又降低了运行效率;②对于集合卡尔曼滤波,初始场的估计是否准确对同化系统性能影响不大;③模型误差和观测误差的准确估计可以提高土壤水分的估计精度;④利用数据同化的方法对土壤水分的估计有显著提高。 相似文献
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The analytical solution of soil pore pressure accumulations due to a progressive wave is examined in detail. First of all, the errors contained in a published analytical solution for wave‐induced pore pressure accumulation are addressed, and the correct solution is presented in a more general form. The behaviour of the solution under different soil conditions is then investigated. It is found that the solution for deep soil conditions is sensitive to the soil shear stress in the top thin layer of the soil. However the solution is significantly influenced by the shear stress in the thin layer of soil near the impermeable base, for shallow and finite depth soil conditions. It is also found that a small error in the soil shear stress can lead to a large error in the accumulated pore pressure. An error analysis reveals the relationships between the accuracy of the pore pressure accumulation and the accuracy of the soil shear stress. A numerical solution to the simplified Biot consolidation equation is also developed. It is shown that the error analysis is of significant value for the numerical modelling of pore pressure buildup in marine soils. Both analytical and numerical examples are given to validate the error estimation method proposed in the present paper. Copyright © 2001 John Wiley & Sons, Ltd. 相似文献