Test Site Conditions Research Articles

Adjusted Controlled Pass-By (CPB) Method for Urban Road Traffic Noise Assessment

Noise associated with road infrastructure is a prominent problem in environmental acoustics, and its implications with respect to human health are well documented. Objective and repeatable methodologies are necessary for testing the efficacy of sustainable noise mitigation methods such as low noise emission pavement. The Controlled Pass-By (CPB) method is used to measure the sound generated by passing vehicles. Despite its popularity, the applicability of CPB is compromised in urban contexts, as its results depend on test site conditions, and slight changes in the experimental setup can compromise repeatability. Moreover, physical conditions, reduced space, and urban elements risk confine its use to only experimental road sites. In addition, vehicle speed represents a relevant factor that further contributes to the method’s inherent instability. The present paper aims to extend the applicable range of this method and to provide more reliable results by proposing an adjusted CPB method. Furthermore, CPB metrics such as LAmax do not consider the travelling speed of the vehicle under investigation. Our proposed method can yield an alternative metric that takes into account the duration of the noise event. A hypothetical urban case is investigated, and a signal processing pipeline is developed to properly characterize the resulting data. Speed cushions, manhole covers, and other spurious effects not related to the pass-by sound emissions of ordinary vehicles are pinpointed as well.

Research on cemented artificial pillars to replace protective inter-block coal pillars and stope failure laws

Replacing protective inter-block coal pillars (PICPs) with cemented artificial pillars is proposed here to address low coal recovery rates. The use of cemented artificial pillars also reduces resource waste when PICPs are used in the short-wall block mining (SBM) process. A coal mine test area in northern Shaanxi, China, was employed as the study site. Artificial pillar replacement techniques were developed based on the layout characteristics of a typical SBM workface. High-strength cemented backfill materials for artificial pillars were manufactured using innovative material ratio testing, and the optimum ratios for backfill materials are discussed. A cusp catastrophe model of an artificial pillar was then developed and used to deduce the conditions and critical widths necessary to generate catastrophic instability of an artificial pillar. This theoretical analysis was validated using FLAC3D simulations. Using the test site conditions, the simulations revealed that when an artificial pillar had a width of 14 m, the destruction of the pillar and associated stope was gradual and would not cause catastrophic instability. Field monitoring performed at the test site verified the theoretical analysis and numerical simulation results, confirming that it was feasible to replace PICPs with cemented artificial pillars.

Intelligent Vehicle Test and User Condition Correlation Evaluation Model

To research the quantitative evaluation of the effectiveness of intelligent vehicles from user operating conditions to test operating conditions in proving ground, a matching model and evaluation model of intelligent vehicle test condition and user condition was presented on the basis of theory of human-vehicle-road cooperative driving risk field by comprehensively considering the acceleration coefficient, risk coverage, maximum risk, and risk distribution of user conditions and test site conditions. With the vehicle following scene taken as an example and with the JT/T 1242-2019, GB/T 33577-2017, and ISO 22839 standards used as reference, the validity of the actual operating condition data of users and the operating condition data of the test site was analyzed and evaluated by using the correlation evaluation model. Results showed that the research results can be used to quantitatively evaluate the effectiveness of different intelligent vehicle test conditions.

Identification of Water Body Extent Based on Remote Sensing Data Collected with Unmanned Aerial Vehicle

The paper presents an efficient methodology of water body extent estimation based on remotely sensed data collected with UAV (Unmanned Aerial Vehicle). The methodology includes the data collection with selected sensors and processing of remotely sensed data to obtain accurate geospatial products that are finally used to estimate water body extent. Three sensors were investigated: RGB (Red Green Blue) camera, thermal infrared camera, and laser scanner. The platform used to carry each of these sensors was an Aibot X6—a multirotor type of UAV. Test data was collected at 6 sites containing different types of water bodies, including 4 river sections, an old river bed, and a part of a lake shore. The processing of collected data resulted in 2.5-D and 2-D geospatial products that were used subsequently for water body extent estimation. Depending on the type of used sensor, the created geospatial product, and the type of the water body and the land cover, three strategies employing image processing tools were developed to estimate water body range. The obtained results were assessed in terms of classification accuracy (distinguishing the water body from the land) and geometrical planar accuracy of the water body extent. The product identified as the most suitable in water body detection was four bands RGB+TIR (Thermal InfraRed) ortho mosaic. It allowed to achieve the average kappa coefficient of the water body identification above 0.9. The planar accuracy of water body extent varied depending on the type of the sensor, the geospatial product, and the test site conditions, but it was comparable with results obtained in similar studies.

External Ballistics Simplified Model of the “RT – 400” Rocket Aerial Target

“RT-400” rocket aerial target system is described in the paper; research method of its simplified external ballistics characteristics is presented and the obtained results are discussed. This system was designed, tested, and produced by a research team of the Institute of Defence Technologies at Kaunas University of Technology and successfully implemented in practice. One of main aims of this paper was to develop external ballistics’ model of a rocket propelled aerial target which would enable obtaining various ballistic parameters of the investigated vehicle such as its acceleration, velocity, flight angle, flight range and trajectory using as input the internal ballistics data obtained at earlier experimental research of the “RV-12K” rocket motor in a static horizontal test stand for thrust measurements and determination of other internal ballistics’ characteristics such as combustion chamber temperature and pressure. During the experimental research process of the vehicle, under test site conditions, the main aim was to compare accuracy of the obtained external ballistics simulation data with the data obtained during experimental approaches using additional measurement techniques such as radar tracking and crash site and launch site GPS coordinates marking.

Electric resistivity and seismic refraction tomography: a challenging joint underwater survey at Äspö Hard Rock Laboratory

Abstract. Tunnelling below water passages is a challenging task in terms of planning, pre-investigation and construction. Fracture zones in the underlying bedrock lead to low rock quality and thus reduced stability. For natural reasons, they tend to be more frequent at water passages. Ground investigations that provide information on the subsurface are necessary prior to the construction phase, but these can be logistically difficult. Geophysics can help close the gaps between local point information by producing subsurface images. An approach that combines seismic refraction tomography and electrical resistivity tomography has been tested at the Äspö Hard Rock Laboratory (HRL). The aim was to detect fracture zones in a well-known but logistically challenging area from a measuring perspective. The presented surveys cover a water passage along part of a tunnel that connects surface facilities with an underground test laboratory. The tunnel is approximately 100 m below and 20 m east of the survey line and gives evidence for one major and several minor fracture zones. The geological and general test site conditions, e.g. with strong power line noise from the nearby nuclear power plant, are challenging for geophysical measurements. Co-located positions for seismic and ERT sensors and source positions are used on the 450 m underwater section of the 700 m profile. Because of a large transition zone that appeared in the ERT result and the missing coverage of the seismic data, fracture zones at the southern and northern parts of the underwater passage cannot be detected by separated inversion. Synthetic studies show that significant three-dimensional (3-D) artefacts occur in the ERT model that even exceed the positioning errors of underwater electrodes. The model coverage is closely connected to the resolution and can be used to display the model uncertainty by introducing thresholds to fade-out regions of medium and low resolution. A structural coupling cooperative inversion approach is able to image the northern fracture zone successfully. In addition, previously unknown sedimentary deposits with a significantly large thickness are detected in the otherwise unusually well-documented geological environment. The results significantly improve the imaging of some geologic features, which would have been undetected or misinterpreted otherwise, and combines the images by means of cluster analysis into a conceptual subsurface model.

Interaction processes at the concrete-bentonite interface after 13 years of FEBEX-Plug operation. Part I: Concrete alteration

This paper evaluates the modifications created in the concrete of the FEBEX shotcreted concrete plug after 13 years in the Grimsel Test Site conditions. During this time the concrete interacted with granite groundwater and also with bentonite porewater at the concrete/bentonite contact. Three long cores and 6 small cores from different parts of the concrete plug were evaluated. Mechanical performance was not modified during this time but hydraulic conductivity increased. The main transport mechanisms involved in the alteration of the concrete were groundwater flow from the host rock to the concrete and diffusion at the concrete/bentonite interface. Leaching occurred in the concrete parts near the host rock due to the action of granite water with further portlandite dissolution. The joint action of granite groundwater and bentonite porewater has caused many changes to the concrete matrix which was located at a depth lower than 5 cm from the bentonite-concrete interface. In the first centimetre C-S-H was significantly altered, incorporating elements like Al, S and Mg which change the initial microstructure by loss of compactness. The ettringite content was very high along the length of the concrete plug due to the shotcreting technique which made use of accelerator additives that caused the formation of ettringite. An increase in the ettringite content is also shown near the bentonite barrier. Therefore, sulphate diffused from the bentonite into the concrete, causing the massive formation of new ettringite. Chloride also diffused from the bentonite barrier deeper into the concrete by up to 4–5 cm from where the formation of Friedel's salt was detected.

Effect of Tire Configuration on the Performance of a Low-Volume Road Exposed to Heavy Axle Loads

A series of response measurements was conducted at an instrumented low-volume road test site to determine the effects of different tire con-figurations of a heavy vehicle on the performance of the road structure. After the measurements were made, a true three-dimensional finite element model was developed with PLAXIS 3D 2012 software. The aim of the modeling was to find explanatory factors between the measured stress–strain relationships and confirmed permanent deformations, rutting in particular, at test site conditions. A model was created with reasonable material parameters. The model produced stress levels and road surface deflections that are comparable with the measured values. The mobilizing levels of shear strains seem to explain the notable permanent deformation at the test site despite the relatively low amount of heavy traffic. The shear strain levels can also be used as an efficient tool in evaluating the effects of other variables, such as road structural layers, construction materials, and environmental conditions, on the risk that structural deterioration of roads may occur when the intensity of loading increases.

Radiated ship noise level estimates from measurements in a fjord

This paper presents estimates of radiated ship noise levels (20 Hz—1 kHz) due to commercial shipping in the Oslofjord (Norway). Data were recorded at two Networked Intelligent Underwater Sensors (NILUS) units, each equipped with an omni-directional hydrophone placed near the seabed, at water depths of 45 and 110 m, respectively. Received noise levels due to traffic in two nearby shipping lanes (ranges, 0.4–3.0 km) were for these non-ideal test site conditions processed and corrected to monopole source levels by use of the RAM propagation model with range estimates from auxiliary data, environmental input from a prior survey of the area, and a vertically distributed source model [Trevorrow et al., J. Acoust. Soc. Am. 124(2), 767–778] to model uncertain source depth. Estimates of source spectra and of broadband source levels of cargo ships are presented and compared with deep-water measurements from the literature.

충돌하중을 받는 이방향 비부착 프리스트레스트 콘크리트 패널부재의 충돌저항성능에 대한 실험적 거동 평가

2001년 9.11테러로 인한 미국 세계무역센터 및 미국 국방성 펜타곤이 붕괴된 이후, 전 세계적으로 충돌, 폭발 등의 극한하중에 의한 테러가 빈번하게 발생하고 있으며, 극한하중에 의한 구조물의 거동에 대한 사회적 불안감은 더욱 증가되고 있다. 그러나 지금까지의 사회기반시설구조물에는 폭발 및 충돌 등과 같은 극한하중에 대한 방호 및 방재개념을 설계에 고려하지 못하고 있는 실정이며, 원전격납건물, 가스탱크, 교량, 터널 등에 널리 사용되는 프리스트레스트 콘크리트 구조물에 대한 극한하중 연구는 전 세계적으로 미흡하다. 충돌과 같은 극한하중은 집약된 에너지의 급작스런 방출로 인한 높은 충돌압력을 형성하므로, 극한하중의 특성 및 전파 메커니즘을 이해하는 것이 필요하다. 그러므로 이 연구에서는 이방향 비부착 프리스트레스트 콘크리트 패널의 충돌저항성능을 비교검토하기 위하여, 1400 mm×1000 mm×300 mm의 철근콘크리트(RC), 프리스트레스 텐던으로만 보강된 콘크리트(PS), 프리스트레스 텐던과 철근으로 보강된 콘크리트(PSR, 일반적인 PSC) 시편을 제작하였다. 실험 조건에 맞춰 14 kN의 추를 10 m, 5 m, 4 m 높이에서 낙하하는 예비 실험과 3.5 m 높이의 본 실험으로 구성하여 충돌하중에 대한 프리스트레스트 콘크리트 구조물의 실험적 평가를 수행하였다. 또한, 충돌실험을 위한 기본적인 실험 구성 및 계측시스템을 구축하였다. 충돌 저항성능은 균열형상, 손상면적, 에너지 흡수, 처짐, 변형률, 가속도 등의 충돌에 의한 계측데이터를 이용한 거동분석 뿐만 아니라, 충돌 후 잔류구조성능 실험을 수행하여 이방향 비부착 프리스트레스트 콘크리트 패널의 충돌저항성능을 검토하였다. 본 실험은 향후 국내외 프리스트레스트 콘크리트에 대한 충돌 방호설계 및 충돌해석 등 관련 연구분야의 기초자료가 될 것이라고 판단되는 바이다.

Cross well radar and vertical radar profiling methods for time lapse monitoring of rainfall infiltration

The relationship between electromagnetic velocities derived from in-hole radar surveying and soil saturation can be exploited to map changes in recharge from rainfall infiltration in the vadose zone against time. We have completed time-lapse cross-well radar and vertical radar Profiling (VRP) experiments with the objective of monitoring rainfall infiltration during the winter season at two sites on the Gnangara Mound in the Perth Basin, Western Australia. Depth-velocity profiles have been derived from the direct transmission measurements. Results obtained from Vertical Radar Profiling and Zero vertical offset cross well profiling are evaluated and the influence of different geometries and test-site conditions are discussed. We find that zero vertical offset cross well radar experiments were highly repeatable. Further changes in ground conditions such as an increase in moisture content can be observed with great confidence. The interpretation of vertical radar profiles was more challenging. However both techniques successfully reveal the time-lapse response of water migrating through the unsaturated soil profile for the two trial sites.

Evaluation of Soil Vapor Extraction and Bioventing for a Petroleum-Contaminated Shallow Aquifer in Korea

The feasibility of soil vapor extraction and bioventing technologies was examined for a petroleum hydrocarbon-contaminated site. The test site was highly contaminated with toluene, ethylbenzene, and xylene, due to leakage from petroleum storage tanks. Three respiration tests demonstrated that the test site conditions were appropriate for application of air-based remediation technologies. The oxygen consumption rates ranged from 4.32 to 7.68 %-O2/day and biodegradation rates ranged from 2.72 to 4.84 mg/kg-day in respiration tests. In a 120-day soil vapor extraction pilot test, high initial mass removals (with tailing effects) were observed. As expected for the soil vapor extraction, the volatilization rate was much higher than the biodegradation rate. In a bioventing trial, the biodegradation effect was predominant, but a tailing effect was not observed. From this study, the suggested sequence of remediation is to construct an integrated system of soil vapor extraction and bioventing and initially operate the soil vapor extraction system until the volatilization rate becomes smaller than the biodegradation rate. After that, the system needs to be changed over to a bioventing mode. Field demonstration supports the feasibility of the proposed integrated system.

AASHTO Drainage Coefficients for Flexible Pavements

A method for determining AASHTO drainage ( m) coefficients for flexible pavements is presented. In essence, m coefficients were developed as ratios of the layer coefficients of the AASHO road test granular base material under any given drainage and climate condition to the layer coefficient of the road test base material under road test site conditions. The layer coefficients were calculated from resilient moduli determined for various conditions by use of elastic layered analysis. The moduli were varied by changing subgrade and base moisture conditions for any given time of year. The base material moisture sensitivity (effect on θ model constants k1 and k2) was determined, in part, by the resilient modulus laboratory testing of granular materials. The result of the preceding analysis was the creation of a set of tables that guide the designer to a choice of m coefficients. The new m values can be used to provide a rational measure of the influence of pavement drainage on pavement performance.

Engineering properties of nuclear craters. Report I. Site selection investigations, wet medium cratering experiments: R. T. Saucier and D. C. Banks.Army engineer waterways experiment station, Vicksburg, Miss.

Abstract : Investigations were conducted to select a site suitable for producing craters in a saturated cohesive medium by small-scale high-energy detonations. According to prescribed criteria, the ideal site would be a large (200 acres or more), cleared, moderately flat tract of Federally owned land characterized by soft, homogeneous clays to a minimum depth of 40 feet. An evaluation of the U. S. by physical divisions revealed that suitable sites might occur in four general areas, i.e. (1) the Lake Bonneville area, (2) the Lake Agassiz area, (3) the Great Lakes area, and (4) the Lower Mississippi Valley area. Acquisition and analyses of pertinent data on these areas indicated a need for field reconnaissances except in the case of the Great Lakes area which was eliminated from further consideration because of heterogeneous soil deposits. A reconnaissance of the Lake Bonneville area indicated the presence of apparently favorable test site conditions in a portion of the Dugway Proving Ground, Utah. The Dugway site was concluded to be the most suitable for the project. (Author)