The influence of signal noise to measurements at bridge structure

Bridge weight-in-motion (BWIM) system is a method, that provides to identify axle weights. It is a non-destructive method, which allows not only to identify the axle weight, but it can show current shape of the structure, so it has a great potential. There are various methods to do measurements for this system. Mostly, accelerometers or strain gauge are used. Signal noise has significant effects to the results. It could be resonance of the bridge, wind, defect at the support system, defect at the roadway, etc. It is necessary to filter all this effects, to get clear data. There are many ways to do the filtering. Digital filters allow it. Sometimes, this type of filtering could remove important data about the crossing of the vehicle. It could generate inaccuracy of the whole system and create major errors to identified vehicles. It is necessary to find the optimal way, to keep important data and remove all dynamic noise. This paper will investigate the previously mentioned problems. Measurements will be accomplished on a small-scale model of the bridge. Vehicle will be crossing over the bridge, while the bridge will be awakened to the first vibration shape and other frequencies, that will have a great impact to the measurements.

Simulation of a small scale model of dike susceptible to suffusion

<p>Suffusion is characterized by a migration of the fine particles within a given volume of soil under the effect of flow. This complex phenomenon involves simultaneous detachment, transport and possible filtration of the fine fraction. With the objective to reproduce the amplitude and the kinetics of the suffusion process within a small scale model of dike, a poro-elastic model accounting for suffusion is implemented in a FEM code. The rate of eroded mass is modeled by a constitutive relation named the energy-based law [1], which is inspired from the energy-based approach [2]. This relationship uses two key parameters that describes the end of the suffusion process: the erosion resistance index and the maximum cumulative expended volumetric energy. An additional parameter named the smoothing time, which controls the kinetics of the suffusion process, is used to account for the history of the power dissipated by the flow. These three parameters are calibrated on a first specimen which was experimentally suffused up to a stable state of erodibility.</p><p>Next, a small scale model of dike is simulated using the poro-elastic model extended to suffusion. This dike model, which was experimentally tested by Rochim [3], is assumed to be initially homogeneous and characterized by an isotropic permeability. To illustrate the capability of the energy-based relationship in tackling the suffusion process, the FEM results using the energy-based relationship are compared with the experimental measurements. The dike behavior is investigated in terms of downstream flow rate, total water head at specific pressure ports, cumulative eroded mass and post-suffusion spatial distribution of the percentage of fines. The energy-based approach is able to predict the total amount of cumulative eroded mass, the correct magnitude of the percentage of fines variation and a smoother version of the spatial distribution of the fine particles at the end of the suffusion process.</p><p><strong>REFERENCES</strong></p><ul><li>[1] Kodieh, A., Gelet, R., Marot, D., & Fino, A. Z. (2020). A study of suffusion kinetics inspired from experimental data: comparison of three different approaches. Acta Geotechnica, 1-19.</li> <li>[2] Marot, D., Le, V. D., Garnier, J., Thorel, L. and Audrain, P., 2012. Study of scale effect in an internal erosion mechanism: centrifuge model and energy analysis. European Journal of Environmental and Civil Engineering, 16(11), 1-19.</li> <li>[3] Rochim A., Characterization of suffusion susceptibility of granular soils. PhD thesis, Université de Nantes, 2015.</li> </ul>

Hydro-Mechanical Modeling of the Year 2000 Hydraulic Stimulation of GPK2 Well, Soultz-sous-Forêts, France

<p> Hydraulic stimulation of pre-existing fractures and faults plays a significant role in improving hydraulic conductivity of the fracture network around injection and production wells in geothermal reservoirs. It is therefore important to characterize the hydro-mechanical behavior of the faults against fluid injection. The Soultz-sous-Forêts site (France) has been an EGS pilot site where several major hydraulic stimulations have been performed and are well documented (https://cdgp.u-strasbg.fr/ and https://tcs.ah-epos.eu/).</p><p>Here we use the 3DEC numerical modeling tool (Itasca) to analyze the year 2000 stimulation of GPK2 well where large scale seismic anomalies have been evidenced during the different stages of the stimulation using 4D-P-wave tomography (Calo et al, 2011). The specificity of the approach is to combine two modeling at different scales. First, a small-scale model (100x100x100 m<sup>3</sup>) is built to analyze the effective mechanical response of a stochastic discrete fracture network (DFN) following the statistical features of the observed fracture network (Massart et al, 2010). Second, a large-scale numerical model of the Soultz-sous-Forêts reservoir (5000x5000x5000 m<sup>3</sup>) containing the largest faults of the reservoir defined by Sausse et al., 2010, is developed including regional stresses. The objective is to constrain the large-scale mechanical properties of the surrounding matrix around the fault from the small-scale model, in particular, its hydro-mechanical behavior in terms of non-linear elastic response related to the stochastic DFN. As a first step only the largest fault (GPK3-FZ4770) is considered. The first stage of the stimulation is modelled as a constant flow rate of 30 ls<sup>-1</sup> of water injected into the fault at the depth of approximately 4.7 km. We explored the effect of the normal and shear stiffness of the fault on the dynamical response of pore pressure along the fracture and the onset of slip. It is found that the increase of the aperture of the fault during the injection shows a slow migration (~2 cm/s) owing to poro-elastic effects. Also generated fluid pressure throughout the fault shows a long period oscillating behavior (~5 hr) sensitive to the magnitude of the fracture normal stiffness.</p>

PENGARUH KOMPETENSI KEWIRAUSAHAAN TERHADAP KINERJA USAHA KEDAI KOPI SKALA MIKRO DAN KECIL DI KOTA MEDAN

<em>This research aims to analyze the influence of entrepreneurial competency towards the business performance of micro and small scale coffee shop in Medan City. Entrepreneurial competency reflected by managerial skill, conceptual skill, social skill, decision making skill and time managerial skill. Business performance reflected by income, profit and sales volume. This research used 60 data samples of coffee shop consist of 30 unit micro scale and 30 unit small scale that were collected through snowball sampling in Medan City from February 2020 until March 2020. The data were analyzed by SEM-PLS analysis with SMART PLS 3 software. The result showed that the business performance was influenced by entrepreneurial competency both in micro and small scale model.</em>

Experimental Tests on a Small-Scale Model of a Mine Stope to Study the Behavior of Waste Rock Barricades during Backfilling

This paper presents a reduced-scale physical model of a mine stope used to reproduce the underground stope backfilling practiced in some Canadian mines. The objective is to study the geomechanical behavior of the waste rock barricades in interaction with the mine backfill. The instrumentations, along with visual observations and preliminary results, are presented. The main results demonstrated that: (i) the stability of the barricade depends on its physical properties (e.g., size, location, particles gradation and compaction) and the frictional behavior at the barricade/drift walls interface, and (ii) for two backfill formulations, cemented and uncemented, prepared with 70% of solid mass concentration, the volumetric strain due to self-weight consolidation of the backfilled room was higher for uncemented backfill (16%) than for the cemented one (4.5%). In addition, the results highlighted the importance of using shotcrete around the downstream face of the barricade, mostly at the top, to close the gaps and bind the barricade particles, which improves its stability.

Wave overtopping and splash-up at seawalls with bullnose

Seawalls have been erected to protect hundreds of towns and tourism areas stretching along the coast of Vietnam. During storm surges or high tides, wave overtopping and splash-up would often threaten the safety of infrastructures, traffic and residents on the narrow land behind. Therefore, this study investigates these wave-wall interactions via hydraulic small scale model tests at Thuyloi University. Remarkably, the structure models were shaped to have different seaward faces and bullnoses. The wave overtopping discharge and splash run-up height at seawalls with bullnose are significantly smaller than those without bullnose. Furthermore, the magnitude of these decreasing effects is quantitatively estimated.