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Attenuation of ground vibrations due to different technical sources

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Earthquake Engineering and Engineering Vibration 2010年第3期9卷 337-344页

作者： L.Auersch S.Said Federal Institute of Material Research and Testing

The attenuation of technically induced surface waves is studied theoretically and experimentally. In this paper, nineteen measurements of ground vibrations induced by eight different technical sources including road and rail traffic, vibratory and impulsive construction work or pile driving, explosions, hammer impulses and mass drops are described, and it is shown that the technically induced ground vibrations exhibit a power-law attenuation v - r ~ where the exponents q are in the range of 0.5 to 2.0 and depend on the source types. Comparisons performed demonstrate that the measured exponents are considerably higher than theoretically expected. Some potential effects on ground vibration attenuation are theoretically analyzed. The most important effect is due to the material or scattering damping. Each frequency component is attenuated exponentially as exp（-kr）, but for a broad-band excitation, the sum of the exponential laws also yields a power law but with a high exponent. Additional effects are discussed, for example the dispersion of the Rayleigh wave due to soil layering, which yields an additional exponent of 0.5 in cases of impulsive loading.

关键词： wave attenuation environmental vibrations field tests material damping scattering damping Rayleigh wave

Analysis of microclimate characteristics in solar greenhouses under natural ventilation

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Building Simulation 2021年第6期14卷 1811-1821页

作者： Yicun Hou Angui Li Yue Li Dacheng Jin Yu Tian Da Zhang Dingmeng Wu Linhua Zhang Wenjun Lei School of Building Services Science and Engineering Xi'an University of Architecture and TechnologyXi'anShaanxi 710055China School of Thermal Engineering Shandong Jianzhu UniversityJinanShandong 250101China

The solar greenhouse is a typical greenhouse type in northern *** provides a favorable environment for the growth of various plants and extends cultivation periods for almost a whole year to achieve a high ***,indoor environmental control is primarily based on growers'experience,and the objective test data required for the complex climate control and management of greenhouses are *** present study used three greenhouses in northwest China as research objects:one greenhouse with mature plants(GH-M),one greenhouse with young plants(GH-Y)and one greenhouse without plants(GH-E).field tests were performed to investigate microclimate characteristics,such as indoor air temperature,relative humidity,and solar radiation under natural *** results showed that the maximum temperature difference reached approximately 8.2℃in the vertical direction,and semiempirical equations for the normalized temperature distribution were *** soil temperature remained constant at a certain depth(0.4 m).The distribution of the relative humidity and solar radiation was *** current study is helpful for growers to develop better greenhouse climate control strategies for management practices.

关键词： solar greenhouse field tests microclimate natural ventilation

Advanced methods of cell phone localization for crisis and emergency management applications

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International Journal of Digital Earth 2015年第4期8卷 259-272页

作者： Tomas Reznik Bronislava Horakova Roman Szturc Department of Geography Masaryk UniversityBrnoThe Czech Republic Intergraph CS PragueThe Czech Republic

Real-time people localization cannot be achieved through statistical methods during crisis/emergency management *** International Mobile Subscriber Identity(IMSI)catcher was proposed as a nontraditional method for cell phone-based people *** verified the idea of using a cell phone as a sensor and tested the possibility of transmitting cell phone data through the Open Geospatial Consortium(OGC)Sensor Web *** large field tests were performed and are described in *** main conclusions for IMSI catcher deployment were search within a limited radius from its placement and the number of localized people was not a limiting aspect;although the technology for advanced cell phone-based localization is available for crisis/emergency management applications,we do not yet have sufficient ability to handle this technology.

关键词： emergency support system field tests IMSI catcher sensor web enablement

Effects of deep soil mixing on existing shield tunnels in soft soil ground

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Underground Space 2022年第4期7卷 724-733页

作者： Huangsong Pan Liyuan Tong Zhansheng Wang Tao Yang Institution of Geotechnical Engineering Southeast UniversityNanjing 210096China Senior Engineer Suzhou Rail Transit Group LtdSuzhou 400045China

To mitigate the impact of adjacent construction on existing shield tunnels,deep soil mixing(DSM)has been widely used to reinforce the soft soil ground around shield ***,the construction of DSM may cause the movement of existing shield tunnels under soft soil and sensitive ground conditions,and reasonable installation parameters will reduce the impact of DSM construction on the existing shield *** on the field tests of DSM installation parameters and a program of field measurements of existing shield tunnels during the DSM construction in Suzhou,the reasonable installation parameters of DSM were selected,and the movement of soil behind the soil mixing walls(SMWs)during multirow DSM installation was *** movement of the shield tunnels caused by DSM construction were discussed in *** field test results showed that the DSM columns installed at a higher speed and a lower water-cement ratio enlarged the movement of the surrounding *** DSM should be installed at a lower speed and a higher watercement ratio to reduce the movement of the shield *** field measurement results showed that the displacement of the tunnel lining was primarily caused by the construction of DSM zones beside the shield tunnels,which led to vertical compression and horizontal expansion of the tunnel *** construction of DSM immediately above the shield tunnels caused uplift to the *** addition,the deformed shapes of the two shield tunnels were asymmetric,and the displacement of the spring lining was larger than that of the *** taking the reasonable installation parameters of DSM and under the protection of the SMWs,the deformation of the shield tunnels caused by the construction of DSM was effectively controlled,and the maximum displacement was within the control value of the shield tunnels in this study.

关键词： Deep soil mixing Soft soil Shield tunnel field tests field measurement

field testing of shear strength of granite residual soils

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第9期16卷 3718-3732页

作者： Song Yin Pengfei Liu Xianwei Zhang Wenyuan He Pan Yan Yuzhou Sun School of Civil Engineering and Architecture Zhongyuan University of TechnologyZhengzhou450007China State Key Laboratory of Geomechanics and Geotechnical Engineering Institute of Rock and Soil MechanicsChinese Academy of SciencesWuhan430071China

The characteristics of residual soils are very different from those of sedimentary *** the strength characteristics of sedimentary soils have been studied extensively,the shear strength characteristics of granitic residual soils(GRS)subjected to the weathering of parent rocks have rarely been *** this study,the shear strength characteristics of GRS in the Taishan area of southeast China(TSGRS)were studied by field and laboratory *** field tests consisted of a cone penetration test(CPT),borehole shear test(BST),self-boring pressuremeter test(SBPT),and seismic dilatometer Marchetti test(SDMT).The shortcomings of laboratory testing are obvious,with potential disturbances arising through the sampling,transportation,and preparation of soil *** to the special structure of GRS samples and the ease of disturbance,the results obtained from laboratory tests were generally lower than those obtained from situ *** CPT and scanning electron microscopy(SEM)results indicated significant weathering and crustal hardening in the shallow *** resulted in significant differences in the strength and strength parameters of shallow soil obtained by the *** on the SDMT and SBPT results,a comprehensive evaluation method of shear strength for TSGRS was *** SBPT was suitable for evaluating the strength of shallow *** material index(ID)and horizontal stress index(KD)values obtained by the SDMT satisfied the empirical relationship proposed by Marchetti based on the ID index,and were therefore considered suitable for the evaluation of the shear strength of deep GRS.

关键词： Granite residual soils Shear strength field tests Self-boring pressuremeter Seismic dilatometer Borehole shear test

Optimizing the design of in situ sediment oxygen demand measurement chambers

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International Journal of Sediment Research 2011年第2期26卷 222-229页

作者： HE Yun and LIU Cheng 1 Senior Engineer,Dr.,China Institute of Water Resources and Hydropower Research,Beijing 100038,China, 2 Prof.,Dr.,International Research and Training Center on Erosion and Sedimentation,Beijing 100048,China [a]Senior Engineer Dr. China Institute of Water Resources and Hydropower Research Beijing 100038 China [b]Prof. Dr. International Research and Training Center on Erosion and Sedimentation Beijing 100048 China

Sediment Oxygen Demand(SOD) is a key parameter for water quality analysis and for water quality modeling in rivers,lakes,estuaries and *** SOD can be measured both in the laboratory and in ***,the in situ technique appears to be the better approach for measuring SOD,as it likely to provide more representative and accurate *** order to optimize the design of in situ SOD measurement chambers,the three-dimensional flow fields in cylindrical SOD measurement chambers, commonly used for in situ measurements,have been numerically simulated by using the RNG-based k-s double equation turbulence *** chambers with three different inflow pipe configurations were *** results show that chamberⅢpresents distinct advantages over the other designs for in situ SOD measurement,because good flow mixing can be achieved and bottom sediment suspension can be avoided in the *** numerical simulation results were validated by comparison with existing results derived from laboratory *** SOD measurement chamber designed to reflect the results of the numerical simulations was successfully tested for in situ SOD measurements in both fresh and saline waters.

关键词： Sediment Oxygen Demand(SOD) Renormalization group(RNG) Velocity field In situ measurement field tests

field evaluation of selected light sources for roadway lighting

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Journal of Traffic and Transportation Engineering(English Edition) 2018年第5期5卷 372-385页

作者： Yi Jiang Shuo Li Bowen Guan Guangyuan Zhao Dave Boruff Lalit Garg Prakash Patel Department of Building Construction Management Purdue University West Lafayette IN 47907 USA Division of Research and Development Indiana Department of Transportation West Lafayette IN 47906 USA School of Materials Science and Engineering Chang'an University Xi'an 710064 China Indiana Department of Transportation Indianapolis IN 46204 USA

The development of new lighting sources, such as light emitting diode （LED）, induction, and plasma, presented more possible cost effective ways for roadway lighting. A study was therefore conducted for the Indiana Department of Transportation （INDOT} to evaluate the performance and effectiveness of some selected new lighting devices in roadway lighting. This paper describes the field evaluation process and presents the evaluation results. A number of LEDs, plasma and induction luminaires from various manufacturers were selected to replace the existing high pressure sodium （HPS） lamps in conventional and high mast lightings, llluminance values were measured over a period of 12 months on the existing and new light sources. Light performance metrics, including illuminance level and uniformity ratios, were calculated to make quantitative comparisons of the HPS and new types of light devices. Based on the evaluation in terms of lighting performance and life cycle costs, it was concluded that LED luminaires should be utilized in roadway lighting in place of HPS luminaires. The results of this study will be useful to state highway and city street agencies in making decisions on their lighting policies and developing technical specifications for use of the new lighting technologies in roadway and street lightings. The study provides a basis for manufacturers to improve their luminaire design and integration to better fit the needs of roadway and street lightings.

关键词： Roadway lighting Luminaires Illuminance field tests LEDHPS

field trial on use of soybean crude extract for carbonate precipitation and wind erosion control of sandy soil

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Journal of Central South University 2020年第11期27卷 3320-3333页

作者： GAO Yu-feng MENG Hao HE Jia QI Yong-shuai HANG Lei Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering Hohai UniversityNanjing 210098China

Wind erosion is a major cause of land desertification and sandstorm formation in arid and semi-arid *** objective of this study was to evaluate the potential of soybeans crude extract induced calcium carbonate precipitation(SICP)on reducing wind erosion risk of sandy *** tests were carried out in Ulan Buh Desert,Ningxia Hui Autonomous Region,*** showed that the SICP method could significantly enhance the surface strength and wind erosion resistance of the *** optimal cementation solution(urea-CaCl2)concentration and spraying volume,according to experiments conducted on sandy land,were 0.2 mol/L and 4 L/m^2,*** this condition,the CaCO3 content was approximately 0.45%,the surface strength of sandy soil could reach 306.2 kPa,and the depth of wind erosion was approximately zero,after 30 d completion of SICP *** surface strength declined with the increase of time,and long-term sand fixation effects of SICP treatment varied depending on *** wind erosion in the top area of the windward slope was remarkable,sandy soils on the bottom area of the windward slope still maintained a relatively high level of surface strength and a low degree of wind erosion 12 month after SICP *** electron microscopy(SEM)tests with energy dispersive X-ray(EDX)confirmed the precipitation of CaCO3 and its bridge *** findings suggested that the SICP method is a promising candidate to protect sandy soil from wind erosion in desert areas.

关键词： soybeans crude extract induced calcium carbonate precipitation(SICP) biocementation sandy soil erosion controll field tests

Evaluation of the Collapsibility of Soils in the Semiarid Region of Pernambuco, Brazil

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Journal of Civil Engineering and Architecture 2014年第10期8卷 1285-1292页

作者： Silvio Romero de Melo Ferreira Stela Fucale Department of Civil Engineering University of Pernambuco Recife 52041-310 Brazil Department of Civil Engineering Federal University of Pernambuco Recife 52020-220 Brazil Department of Civil Engineering Catholic University of Pernambuco Recife 52020-220 Brazil

Some unsaturated soils may undergo volumetric changes when submitted to an increase in its water content or are inundated under applied loads. This behavior is related to the volumetric instability when the water content is changed. Natural collapsible soils in Brazil are generally found in alluvial, colluvial and residual soils. There are known occurrences of natural collapsible soils in many states of Brasil. In the last two decades, many public projects have been developed in areas where the occurrence of collapsible soils has been associated to geotechnical problems. The present paper devoted to study the collapsible soils in the state of Pernambuco which has been associated with large engineering projects such as housing and irrigation canals. The geotechnical investigation program included test with a field apparatus, called Expanso-colapsometer, which allows the measurement of the field settlements of a small 0.10 m of diameter plate inserted at any depth inside an auger boring hole. Reconnaissance borings with SPT （standard penetration test）, investigation pits with undisturbed block sampling and disturbed samples for laboratory tests were also made in order to assess the type and characteristics of the soil. field tests used the Expanso-colapsometer to measure the settlement of the soil in selected depths under controlled flooding. Laboratory work included double and standard oedometer tests with a controlled rate of water inflow of 1.0 mL/s. It was found that the volume change of the soils when flooded depends on their natural stress state （vertical stress, suction head and structure of soil）.

关键词： Collapsible soils field tests laboratory tests.