Dynamic Deformation Characteristics of Soil in the Tasks of Seismic Micro Zoning

2021 ◽  
Vol 2 (3) ◽  
pp. 41-48
Author(s):  
Oleksandr Kendzera ◽  
Yuliia Semenova
Keyword(s):  
Soil Profile ◽  
Computational Models ◽  
Nonlinear Modeling ◽  
Damping Ratio ◽  
Methodological Approach ◽  
Linear Modeling ◽  
Construction Sites ◽  
Soil Layers ◽  
Equivalent Linear ◽  
Under Construction

The article discusses a technique for determining the nonlinear characteristics of the layers of computational models of the soil profile for the equivalent linear and nonlinear modeling of its response to seismic effects. The results of studying the factors influencing the curves of the strain-dependent shear modulus G (γ) and damping ratio D (γ) are analyzed. Based on the results of the analysis, the main parameters have identified that control the shape of the curves and allow you to quickly select the corresponding curves from the existing database with acceptable accuracy for each layer of the soil profile model. For clayey rocks: this is the plasticity index PL and the depth of occurrence; for sandy rocks: particle size, percentage, and depth. The paper presents the results of studying the effect of relative errors that arise when choosing the curves G (γ) and D (γ) for the soil layers of the computational seismic-geological model on the parameters of the frequency response of the soil, calculated using the equivalent linear modeling of ground vibrations during earthquakes. It was found that errors in determining the strain characteristics of soil layers in the calculation model lead to a shift in the maxima of the amplitude-frequency characteristic, to a change in the amplification factors of oscillations, as well as to the appearance of "false" maxima at high frequencies. The methodological approach to the formation of computational seismic-geological models of soil strata, by introducing the curves G (γ) and D (γ), which reflect the nonlinear properties of the soil, makes it possible to improve the computational methods for determining the resonance properties of soils under construction sites. The most accurate values of the frequency characteristics of the soil strata under construction sites are necessary for the development of effective measures to ensure the seismic resistance of the designed and existing facilities. As a result, the validity and accuracy of determining the quantitative parameters of seismic hazard at the construction and operational sites under study are increased. 

Experimental Validation of an Identification Procedure of Soil Profile Characteristics from Free Field Acceleration Records

2012 ◽  
Vol 3 (1) ◽  
pp. 1-17 ◽  
Author(s):  
Z. Harichane ◽  
H. Afra ◽  
R. Bahar
Keyword(s):  
Soil Profile ◽  
Damping Ratio ◽  
Linear Optimization ◽  
Free Field ◽  
Unit Weight ◽  
New Approach ◽  
Theoretical Function ◽  
Minimization Technique ◽  
Profile Characteristics

In this paper, a new approach for soil profile characterization is validated. The soil characteristics are calculated by fitting the theoretical amplification functions to those obtained experimentally. The identified characteristics have been observed to agree well with those obtained by in situ and laboratory tests. This new approach uses system identification theory and free field records. It is based on formulation of theoretical soil amplification function for two sites in terms of the different parameters of the soil profile layers (thickness, damping ratio, shear wave velocity and unit weight). The theoretical function is smoothed according to the experimental data (spectral ratios) by means of the least squares minimization technique. The function parameters are determined by solving, numerically, a non linear optimization problem. In this approach, soil profile characteristics of two sites can be identified simultaneously, from only a single soil acceleration record at free surface of each site without need of bedrock or outcropping acceleration records. Strong ground motions data recorded during the Boumerdes earthquake (Algeria) of May 21, 2003, are used for the validation.

Root production, mortality and turnover in soil profiles as affected by clipping in a temperate grassland on the Loess Plateau

2019 ◽  
Vol 12 (6) ◽  
pp. 1059-1072
Author(s):  
Lin Wei ◽  
Pengwei Yao ◽  
Guanghua Jing ◽  
Xiefeng Ye ◽  
Jimin Cheng
Keyword(s):  
Loess Plateau ◽  
Soil Profile ◽  
Root Length ◽  
Root Biomass ◽  
Turnover Rate ◽  
Fine Root ◽  
Root Production ◽  
The Loess Plateau ◽  
Soil Layers ◽  
Root Mortality

Abstract Aims Clipping or mowing for hay, as a prevalent land-use practice, is considered to be an important component of global change. Root production and turnover in response to clipping have great implications for the plant survival strategy and grassland ecosystem carbon processes. However, our knowledge about the clipping effect on root dynamics is mainly based on root living biomass, and limited by the lack of spatial and temporal observations. The study aim was to investigate the effect of clipping on seasonal variations in root length production and mortality and their distribution patterns in different soil layers in semiarid grassland on the Loess Plateau. Methods Clipping was performed once a year in June to mimic the local spring livestock grazing beginning from 2014. The minirhizotron technique was used to monitor the root production, mortality and turnover rate at various soil depths (0–10, 10–20, 20–30 and 30–50 cm) in 2014 (from 30 May to 29 October) and 2015 (from 22 April to 25 October). Soil temperature and moisture in different soil layers were also measured during the study period. Important Findings Our results showed that: (i) Clipping significantly decreased the cumulative root production (P < 0.05) and increased the cumulative root mortality and turnover rates of the 0–50 cm soil profile for both years. (ii) Clipping induced an immediate and sharp decrease in root length production and an increase in root length mortality in all soil layers. However, with plant regrowth, root production increased and root mortality decreased gradually, with the root production at a depth of 30–50 cm even exceeding the control in September–October 2014 and April–May 2015. (iii) Clipping mainly reduced root length production and increased root length mortality in the upper 0–20 cm soil profile with rapid root turnover. However, roots at deeper soil layers were either little influenced by clipping or exhibited an opposite trend with slower turnover rate compared with the upper soil profile, leading to the downward transport of root production and living root biomass. These findings indicate that roots in deeper soil layers tend to favour higher root biomass and longer fine root life spans to maximize the water absorption efficiency under environmental stress, and also suggest that short-term clipping would reduce the amount of carbon through fine root litter into the soil, especially in the shallow soil profile.

scholarly journals Lactose-positive intestinal protozoa in objects under construction soil cover of the Samara Region

2017 ◽  
Vol 6 (2) ◽  
pp. 27-31
Author(s):  
Kseniya Yurjevna Vorobjeva ◽  
Nataliya Vladimirovna Prokhorova
Keyword(s):  
Soil Pollution ◽  
Residential Buildings ◽  
Construction Sites ◽  
Intestinal Protozoa ◽  
Utility Systems ◽  
Under Construction ◽  
High Level ◽  
Modern Technologies ◽  
Dangerous Level

Samara Region is one of the largest industrial and agricultural centers of the Russian Federation. It is characterized by a high level of urbanization. Soil degradation, its chemical and bacteriological pollution as well as declining fertility are the result of versatile economic activity in the region. The rate and level of soil pollution are actively monitored however only very scarce data on its sanitary-epidemiological condition are available. At present Samara Region is facing a boost of residential, administrative and industrial constriction which requires sanitary-epidemiological testing of soil at construction sites. The paper deals with the above mentioned problem. It has been determined that the most reliable criteria in estimating the sanitary-epidemiological condition of soil are sanitary-significant microorganisms, a group of coliform bacillus in particular. The causes and effects of urban soil pollution by microbiological contaminants have been analyzed. The role of lactose-positive intestinal protozoa as sanitary-significant microorganisms has been studied. A quantitative evaluation of lactose-positive intestinal protozoa index has been carried out for the soils below residential buildings, administrative buildings, industrial constructions as well as the utility systems area. In particular, it has been measured that the level of soil pollution by lactose positive intestinal protozoa depends on the period they have been in human use. An aggravated level of soil pollution in certain areas can be observed due to uncontrolled littering as well as pet walking or an increasing number of stray animals. Industrialized areas (oil plants) are characterized by the lowest level of lactose positive protozoa contamination which is explained by the fact that those industries use modern technologies which are able to minimize ecological risks. However, such areas are polluted in a different way. Dangerous level of soil contamination by lactose positive protozoa is registered at several large automotive plants.

Nonlinear Approach to Brain Signal Modeling

2011 ◽  
pp. 2834-2839
Author(s):  
Tugce Balli ◽  
Ramaswamy Palaniappan
Keyword(s):  
Signal Processing ◽  
Electrical Activity ◽  
Nonlinear Modeling ◽  
Biological Mechanisms ◽  
Linear Modeling ◽  
Memory Impairments ◽  
Biological Signal ◽  
Biological Signals ◽  
Electrocardiogram Ecg ◽  
Electroencephalogram Eeg

Biological signal is a common term used for time series measurements that are obtained from biological mechanisms and basically represent some form of energy produced by the biological mechanisms. Examples of such signals are electroencephalogram (EEG), which is the electrical activity of brain recorded by electrodes placed on the scalp; electrocardiogram (ECG), which is electrical activity of heart recorded from chest, and electromyogram (EMG), which is recorded from skin as electrical activity generated by skeletal muscles (Akay, 2000). Nowadays, biological signals such as EEG and ECG are analysed extensively for diagnosing conditions like cardiac arrhythmias in the case of ECG and epilepsy, memory impairments, and sleep disorders in case of EEG. Apart from clinical diagnostic purposes, in recent years there have been many developments for utilising EEG for brain computer interface (BCI) designs (Vaughan & Wolpaw, 2006). The field of signal processing provides many methods for analysis of biological signals. One of the most important steps in biological signal processing is the extraction of features from the signals. The assessment of such information can give further insights to the functioning of the biological system. The selection of proper methods and algorithms for feature extraction (i.e., linear/nonlinear methods) are current challenges in the design and application of real time biological signal analysis systems. Traditionally, linear methods are used for the analysis of biological signals (mostly in analysis of EEG). Although the conventional linear analysis methods simplify the implementation, they can only give an approximation to the underlying properties of the signal when the signal is in fact nonlinear. Because of this, there has been an increasing interest for utilising nonlinear analysis techniques in order to obtain a better characterisation of the biological signals. This chapter will lay the backgrounds to linear and nonlinear modeling of EEG signals, and propose a novel nonlinear model based on exponential autoregressive (EAR) process, which proves to be superior to conventional linear modeling techniques.

Vertical distribution of alkali and alkaline earth metals in the soil profile of a wetland - terrestrial ecosystem complex in India

Soil Research ◽  
2007 ◽  
Vol 45 (7) ◽  
pp. 533 ◽  
Author(s):  
B. Anjan Kumar Prusty ◽  
P. A. Azeez
Keyword(s):  
Soil Profile ◽  
Alkaline Earth ◽  
Terrestrial Ecosystem ◽  
World Heritage Site ◽  
Molar Ratio ◽  
Biogenic Elements ◽  
Soil System ◽  
Soil Layers ◽  
Heritage Site ◽  
Ecosystem Complex

We examined the ammonium acetate extractable forms of alkali (Na, K) and alkaline earth (Ca, Li, and Mg) metals in the soil system in a world heritage site, Keoladeo National Park, Bharatpur, India for 3 consecutive years—2003, 2004, and 2005. The metals were assessed along the soil profile, from surface to 1.00 m depth (as 5 layers, at 0, 0.25, 0.50, 0.75, and 1.00 m). Sodium and K were negatively correlated (P < 0.05) and were found in the range 40–4533 and 77–1802 mg/kg, respectively. The distributions of these metals were significantly different among habitats (Na: F = 17.035, K: F = 30.56; P < 0.05). The lowest and highest values of Ca were 548 and 5976 mg/kg, and for Mg 230 and 5654 mg/kg. The variation in Ca was significant among the soil layers (F = 11.9) and among the habitats (F = 117.3, P < 0.05). Li was found in the range 1.74–15.00 mg/kg soil and varied significantly among the soil layers (F = 71.7) as well as habitats (F = 105.9, P < 0.05). Potassium was positively correlated with Ca, Li, and Mg during 2004 and 2005 (P < 0.05). The terrestrial areas in the Park had higher values of Na/K ratio, indicating the dominating presence of Na salts. Calcium-type enrichment in the wetland and Na-type enrichment in the woodland and grassland differentiated the soil in the Park. A low Mg/Ca molar ratio with a range 0.089–1.681 suggests that CaCO3 rocks would not be the major source of Ca in this Park. Since some of the elements were comparatively higher in the soil, the phytocycling of biogenic elements such as Mg and Ca would ultimately improve the fertility status of the soil system in the Park. Although not addressed here, this issue needs to be considered.

Experimental Research on Mechanical Properties of the early-Age Shotcrete

2011 ◽  
Vol 90-93 ◽  
pp. 2188-2192
Author(s):  
Nan Xie ◽  
Jie Ouyang ◽  
Bing Li ◽  
Jing Hui Lu
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Experimental Research ◽  
Early Age ◽  
Construction Sites ◽  
Exponential Relationship ◽  
Construction Period ◽  
Ordinary Concrete ◽  
Under Construction

Abstract. The compressive strength and elastic modulus of early-age shotcrete have important influence on the safety of tunnel during construction period. In order to investigate the laws of the mechanical properties of early-age shotcrete, experiments on the compressive strength and elastic modulus of early-age shotcrete with two different mixes used frequently on construction sites were carried out. The results show that the compressive strength and elastic modulus of shotcrete develop fairly rapidly and especially the development of elastic modulus of shotcrete is faster than that of ordinary concrete. There is an exponential relationship between the compressive strength and time as well as the elastic modulus development and time. Simultaneously their formulas were derived. The research results of this paper are not only helpful to understand the laws of the mechanical properties of early-age shotcrete, but also provide some reference for the reliability analysis of tunnel under construction.

Comparison of Calibrations Modeling for Determination of Protein of Mushroom Base on Middle Infrared Spectroscopy

2011 ◽  
Vol 460-461 ◽  
pp. 357-362 ◽  
Author(s):  
Peng Cheng Nie ◽  
Yan Yang ◽  
Yong He
Keyword(s):  
Infrared Spectroscopy ◽  
Root Mean Square Error ◽  
Latent Variables ◽  
Nonlinear Modeling ◽  
Mean Square ◽  
Linear Modeling ◽  
Fast Determination ◽  
Validation Set ◽  
Middle Infrared

Middle infrared spectroscopy combined with chemometrics was investigated for the fast determination of protein of mushroom. 140 samples (35 for each variety) were selected randomly for the calibration set, whereas, 40 samples for the validation set. After some spectrum preprocessing, linear modeling method (PLS) and nonlinear modeling LS-SVM were constructed. Different latent variables were used as inputs of LS-SVM. The optimal models were obtained with 8 LVs based on LS-SVM. The correlation coefficient,,root mean square error of prediction for the best prediction by LV-LS-SVM were 0.9275, 0.25961. The result indicated that middle infrared spectroscopy combined with LV-LS-SVM could be applied as a high precision and fast way for determination protein of mushroom.

Effects of Soil-Structure Interaction on the Response of a Structure With Tuned Mass Dampers

2015 ◽  
Author(s):  
Chong-Shien Tsai ◽  
Hui-Chen Chen
Keyword(s):  
Soil Structure ◽  
Damping Ratio ◽  
Excitation Frequency ◽  
Soil Structure Interaction ◽  
Entire System ◽  
Mass Ratio ◽  
Tuned Mass Dampers ◽  
Soil Layers ◽  
Structure Interaction ◽  
Multiple Tuned Mass Dampers

This paper aims at examining the effects of soil-structure interaction (SSI) on the response of a structure which is equipped with multiple tuned mass dampers (MTMD) and founded on multiple soil layers overlying bedrock. Closed-form solutions have been obtained for the entire system, which consists of a shear beam type superstructure, multiple tuned mass dampers, and multiple soil layers overlying bedrock, while subjected to ground motion. The proposed formulations simplify the problem in terms of well-known frequency ratios, mechanical impedance and mass ratio, which can take into account the effects of SSI, mass ratio of the MTMD at each excitation frequency and damping ratio in the entire system. These formulations are capable of explicitly interpreting the major dynamic behavior of a structure equipped with multiple tuned mass dampers and interacting with the multiple soil layers overlying bed rock. The SSI effects on the dynamic response of a tuned-mass-damped structure as a result of multiple soil layers overlying bedrock were extensively investigated through a series of parametric studies.

scholarly journals Timber Framing Factor in Toronto Residential House Construction

2021 ◽  
Author(s):  
Rana Qusass
Keyword(s):  
Thermal Control ◽  
Building Envelope ◽  
Construction Sites ◽  
House Construction ◽  
Residential Units ◽  
Residential House ◽  
R Value ◽  
Thermal Bridging ◽  
Under Construction ◽  
The Impact

Achieving energy efficiency with thermal control in residential houses is crucial for the reduction in the energy consumption. Timber framing as the main structural component in the building envelope has a big influence on the effective R-value depending on the framing percentage, and this impacts the overall thermal performance of the building. This project, carried out in Canada, measured the typical framing percentages that are achieved in residential construction sites and compares them with code recommendations. It provides framing factors measured for 17 residential units under construction including detached, row-housing, and semi-detach dwelling units in three different locations in the Toronto area. Detailed on site measurements provide data for numerical calculation to evaluate the amount of framing within external walls, ceilings, and exposed floors. The overall framing factor calculated for each dwelling is found to exceed the recommended percentage by Canadian Model National Energy code for dwellings and ASHRAE Handbook- Fundamental. The research considers the impact that additional regular thermal bridging from the increased framing percentage will have on the effective R-value, and consequently, the impact on thermal effectiveness of the envelope leading to an increase in the overall energy above the expectations of the codes and standards.

scholarly journals The layering of a mountain podzol can strongly affect the distribution of infiltrated water in the soil profile

2018 ◽  
Vol 66 (3) ◽  
pp. 348-356 ◽  
Author(s):  
Lukáš Jačka ◽  
Jiří Pavlásek ◽  
Jana Kalibová ◽  
Petr Bašta ◽  
Martin Kovář ◽  
...  
Keyword(s):  
Soil Profile ◽  
Fine Particles ◽  
Tracer Experiment ◽  
Porous System ◽  
Soil Hydraulic Properties ◽  
Soil Layers ◽  
Dye Tracer ◽  
Limited Entry ◽  
Subsurface Runoff ◽  
Ks Values

Abstract The layering of the soil profile can influence the accumulation of infiltrated water and the way in which subsurface runoff is formed. This paper examines a mountain podzol characterized by clearly developed soil horizons. After these horizons had been identified, distinct soil layers were defined (the eluvial horizon, the spodic horizon (undifferentiated), and weathered bedrock). Saturated hydraulic conductivity (Ks), particle size distribution and bulk density were measured in these layers. A visualization of the distribution of infiltrated water in the podzolic profile was performed using a dye tracer experiment. The accumulation of dyed water and a distinct lateral flow were detected in the eluvial layer. Only limited entry of water into the spodic layer was observed. These effects were caused by changes in soil hydraulic properties (SHP) among the investigated layers. For the spodic horizons, the measured Ks value (crucial SHP) was significantly lower than the Ks values for the other tested horizons. The probable reason for the lower Ks was an accumulation of fine particles and various substances in the spodic horizons, and corresponding changes in the porous system. The observed effects of layering indicate that water can be accumulated and subsurface runoff can be formed over the spodic layer during intensive rain or snow melting.

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