scholarly journals Impact of the Depth of Diaphragm Wall on the Groundwater Drawdown during Foundation Dewatering Considering Anisotropic Permeability of Aquifer

Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 418
Author(s):  
Xu-wei Wang ◽  
Ye-shuang Xu
Keyword(s):  
Diaphragm Wall ◽  
Foundation Pit ◽  
Anisotropic Permeability ◽  
Control Value ◽  
Groundwater Drawdown ◽  
Logarithmic Curve ◽  
Vertical Hydraulic Conductivity ◽  
Practical Engineering ◽  
And Control ◽  
The Impact

Foundation dewatering combined with a waterproof curtain is widely applied to ensure the safety of the foundation pit in areas with multi-aquifer–aquitard alternative strata. The buried depth of the diaphragm wall can influence the environmental effect due to dewatering obviously. This paper investigates the impact of the buried depth of the diaphragm wall on the groundwater drawdown considering the anisotropic permeability of the dewatering aquifer. Numerical simulation is conducted based on an engineering case. The ratio of penetrating depth of diaphragm wall to thickness of dewatering aquifer (RW) and the ratio of horizontal and vertical hydraulic conductivity of dewatering aquifer (RC) are varied. The relationship between approximate hydraulic gradient (Δi) and RW (or RC) can be fitted by Boltzmann curve (or logarithmic curve). Effective, suggested and control values of RW (or RC) are proposed, of which the suggested value is recommended in practical engineering. The effective, suggested and control value of RW can be calculated by logarithmical equation considering the value of RC.

scholarly journals Study on Deformation Law of Deep Foundation Pit with the Top-Down Method and Its Influence on Adjacent Subway Tunnel

2020 ◽  
Vol 2020 ◽  
pp. 1-15
Author(s):  
Yue Gui ◽  
Zhenxing Zhao ◽  
Xiaqiang Qin ◽  
Jianfei Wang
Keyword(s):  
Axial Force ◽  
Ground Deformation ◽  
Diaphragm Wall ◽  
Subway Tunnel ◽  
Top Down ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Maximum Settlement ◽  
The Impact ◽  
The Relationship

Based on a long-term comprehensive instrumentation program, the performance of an excavation pit constructed by the top-down method in downtown Kunming was extensively examined. The measured excavation responses included the deflections of diaphragm wall, vertical column movement, slab axial force, building settlement caused by ground deformation, and the influence of pit excavation on the adjacent subway tunnel. This paper analyses the monitoring data of the existing construction stage. Based on the analyses on the data of field and numerical simulation, the following major findings were obtained: (1) the relationship between the measured maximum wall deflection, δ h m , and excavation depth, H , in this study is δ h m = 0.06 % H ∼ 0.27 % H , which is quite different compared with the relationship of soft-soil pit δ h m = 0.02 % H ∼ 1.2 % H , but closer to the normalized curve of rock-socketed pile δ h m = 0.01 % H ∼ 0.45 % H and rock-socketed diaphragm wall δ h m = 0.031 % H ∼ 0.129 % H . (2) The relationship between the maximum settlement of column ( δ p ) and excavation depth ( H ) is δ p = − 0.09 % ∼ 0.04 % H . The maximum distortion between the diaphragm wall and the column is less than 1/500 of the limit range proposed by Bjerrum. (3) The impact range caused by excavation is about 3.8 times the maximum excavation depth. The ground settlement around the foundation pit is groove type, and the maximum settlement point is located at 2.7 times the maximum excavation depth. (4) The excavation of the foundation pit leads to the maximum vertical settlement of 2 mm and maximum horizontal displacement of 5.2 mm in the subway tunnel; the maximum change of axial force and bending moment are 8.8 kN (the vertical direction) and 6.4 kN·m/m (the horizontal direction), respectively.

scholarly journals Experimental Study for the Embedded Depth of Support Structure Foundation Pit in Granite Residual Soil Area

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Yi-ao Liu ◽  
Chang-ming Wang ◽  
Rui-yuan Gao ◽  
Bai-long Li ◽  
Xiao-yang Liu ◽  
...  
Keyword(s):  
Earth Pressure ◽  
Horizontal Displacement ◽  
Diaphragm Wall ◽  
Residual Soil ◽  
Foundation Pit ◽  
Control Value ◽  
Physical Experiments ◽  
Soil Settlement ◽  
Granite Residual Soil ◽  
Soil Area

In order to deeply understand the appropriate embedded depth of the foundation pit diaphragm wall in granite residual soil area, a physical model of the diaphragm wall with inner support for foundation excavation was constructed according to the actual project in the proportion of 1 : 30. The distribution of Earth pressure, the horizontal displacement of the wall, and the settlement behind the wall were obtained by physical experiments. The numerical simulation was then performed to authenticate the results from physical modeling. It was observed that the embedded depth of the diaphragm wall had the most obvious influence on the horizontal displacement of the wall. Moreover, the final soil settlement and its influence were significantly increased with the decrease in embedded depth. The analysis results also suggested that the control value for the embedded depth of the wall should not be less than 0.36 H (H is the excavation depth of the foundation pit).

scholarly journals Influence of Filter Tube of Pumping Well on Groundwater Drawdown during Deep Foundation Pit Dewatering

Water ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 3297
Author(s):  
Xuehan Zhang ◽  
Xuwei Wang ◽  
Yeshuang Xu
Keyword(s):  
Tube Length ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Deep Foundation Pit ◽  
Depth Difference ◽  
Groundwater Drawdown ◽  
Filter Tube ◽  
Optimal Values ◽  
Closed Pattern ◽  
The Impact

The partial penetrating waterproof curtain combined with pumping wells is widely applied to deep foundation pit dewatering engineering. The filter tube of the pumping well plays a critical role on the environment effect that resulted from foundation pit dewatering. This paper investigated the impact of the filter tube on the groundwater drawdown outside the pit to provide a theoretical basis for the foundation pit dewatering design. Three patterns according to the relative position of the waterproof curtain and the filter tube, which are called wall-well patterns, namely the full-closed pattern, part-closed pattern, and none-closed pattern, have been analyzed. By taking a practice engineering case in Shanghai as an example, the relationship among the proportion of the filter tube length to the dewatering aquifer thickness, the buried depth difference of the wall-well, and the groundwater drawdown difference at both sides of the waterproof curtain are discussed by numerical simulation. The full-closed pattern is the optimal wall-well pattern on the ideal condition. The suggested and optimal values of the filter tube length to the dewatering aquifer thickness are 38.7% and 58.2%. The suggested and optimal values of the buried depth difference of the wall-well are −6.41 m and −1.92 m.

Suppressed, but Not Forgotten

2011 ◽  
Vol 70 (1) ◽  
pp. 5-11 ◽  
Author(s):  
Beat Meier ◽  
Anja König ◽  
Samuel Parak ◽  
Katharina Henke
Keyword(s):  
Memory Trace ◽  
Thought Suppression ◽  
Test Phase ◽  
Indirect Test ◽  
Final Test ◽  
Test Experiment ◽  
And Control ◽  
Cue Words ◽  
The Impact

This study investigates the impact of thought suppression over a 1-week interval. In two experiments with 80 university students each, we used the think/no-think paradigm in which participants initially learn a list of word pairs (cue-target associations). Then they were presented with some of the cue words again and should either respond with the target word or avoid thinking about it. In the final test phase, their memory for the initially learned cue-target pairs was tested. In Experiment 1, type of memory test was manipulated (i.e., direct vs. indirect). In Experiment 2, type of no-think instructions was manipulated (i.e., suppress vs. substitute). Overall, our results showed poorer memory for no-think and control items compared to think items across all experiments and conditions. Critically, however, more no-think than control items were remembered after the 1-week interval in the direct, but not in the indirect test (Experiment 1) and with thought suppression, but not thought substitution instructions (Experiment 2). We suggest that during thought suppression a brief reactivation of the learned association may lead to reconsolidation of the memory trace and hence to better retrieval of suppressed than control items in the long term.

Research Participation Experiences of Informants of Suicide and Control Cases

Crisis ◽  
2010 ◽  
Vol 31 (5) ◽  
pp. 238-246 ◽  
Author(s):  
Paul W. C. Wong ◽  
Wincy S. C. Chan ◽  
Philip S. L. Beh ◽  
Fiona W. S. Yau ◽  
Paul S. F. Yip ◽  
...  
Keyword(s):  
Ethical Issues ◽  
Research Participation ◽  
Self Report ◽  
Initial Contact ◽  
Psychological Autopsy ◽  
Autopsy Study ◽  
The People ◽  
And Control ◽  
The Impact

Background: Ethical issues have been raised about using the psychological autopsy approach in the study of suicide. The impact on informants of control cases who participated in case-control psychological autopsy studies has not been investigated. Aims: (1) To investigate whether informants of suicide cases recruited by two approaches (coroners’ court and public mortuaries) respond differently to the initial contact by the research team. (2) To explore the reactions, reasons for participation, and comments of both the informants of suicide and control cases to psychological autopsy interviews. (3) To investigate the impact of the interviews on informants of suicide cases about a month after the interviews. Methods: A self-report questionnaire was used for the informants of both suicide and control cases. Telephone follow-up interviews were conducted with the informants of suicide cases. Results: The majority of the informants of suicide cases, regardless of the initial route of contact, as well as the control cases were positive about being approached to take part in the study. A minority of informants of suicide and control cases found the experience of talking about their family member to be more upsetting than expected. The telephone follow-up interviews showed that none of the informants of suicide cases reported being distressed by the psychological autopsy interviews. Limitations: The acceptance rate for our original psychological autopsy study was modest. Conclusions: The findings of this study are useful for future participants and researchers in measuring the potential benefits and risks of participating in similar sensitive research. Psychological autopsy interviews may be utilized as an active engagement approach to reach out to the people bereaved by suicide, especially in places where the postvention work is underdeveloped.

Using Work Domain Analysis to Evaluate the Impact of Digitization on Command and Control

2008 ◽  
Author(s):  
Daniel P. Jenkins ◽  
Neville A. Stanton ◽  
Paul M. Salmon ◽  
Guy H. Walker
Keyword(s):  
Command And Control ◽  
Domain Analysis ◽  
Work Domain Analysis ◽  
And Control ◽  
The Impact ◽  
Work Domain

Experimental Study of the Impact of Alisma plantago-aquatica Secretions on Pathogenic Bacteria

2014 ◽  
Vol 1 (3) ◽  
pp. 3-7
Author(s):  
O. Zhukorskyy ◽  
O. Hulay
Keyword(s):  
Pathogenic Bacteria ◽  
Initial Density ◽  
Biologically Active ◽  
Erysipelothrix Rhusiopathiae ◽  
Natural Focus ◽  
Test Species ◽  
Popula Tions ◽  
And Control ◽  
The Impact

Aim. To estimate the impact of in vivo secretions of water plantain (Alisma plantago-aquatica) on the popula- tions of pathogenic bacteria Erysipelothrix rhusiopathiae. Methods. The plants were isolated from their natural conditions, the roots were washed from the substrate residues and cultivated in laboratory conditions for 10 days to heal the damage. Then the water was changed; seven days later the selected samples were sterilized using fi lters with 0.2 μm pore diameter. The dilution of water plantain root diffusates in the experimental samples was 1:10–1:10,000. The initial density of E. rhusiopathiae bacteria populations was the same for both experimental and control samples. The estimation of the results was conducted 48 hours later. Results. When the dilution of root diffusates was 1:10, the density of erysipelothrixes in the experimental samples was 11.26 times higher than that of the control, on average, the dilution of 1:100 − 6.16 times higher, 1:1000 – 3.22 times higher, 1:10,000 – 1.81 times higher, respectively. Conclusions. The plants of A. plantago-aquatica species are capable of affecting the populations of E. rhusiopathiae pathogenic bacteria via the secretion of biologically active substances into the environment. The consequences of this interaction are positive for the abovementioned bacteria, which is demon- strated by the increase in the density of their populations in the experiment compared to the control. The intensity of the stimulating effect on the populations of E. rhusiopathiae in the root diffusates of A. plantago-aquatica is re- ciprocally dependent on the degree of their dilution. The investigated impact of water plantain on erysipelothrixes should be related to the topical type of biocenotic connections, the formation of which between the test species in the ecosystems might promote maintaining the potential of natural focus of rabies. Keywords: Alisma plantago-aquatica, in vivo secretions, Erysipelothrix rhusiopathiae, population density, topical type of connections.

Changes in the Population Density of Pathogenic Microorganisms in Response to the Allelopathic Effect of Thypha Latifolia

2014 ◽  
Vol 1 (1) ◽  
pp. 31-36 ◽  
Author(s):  
O. Zhukorskiy ◽  
O. Gulay ◽  
V. Gulay ◽  
N. Tkachuk
Keyword(s):  
Cell Density ◽  
Allelopathic Effect ◽  
Pathogenic Microorganisms ◽  
Sterile Water ◽  
Erysipelothrix Rhusiopathiae ◽  
Pathogenic Leptospira ◽  
Favorable Conditions ◽  
And Control ◽  
The Impact ◽  
Control Samples

Aim. To determine the response of the populations of Erysipelothrix rhusiopathiae and Leptospira interrogans pathogenic microorganisms to the impact of broadleaf cattail (Thypha latifolia) root diffusates. Methods. Aqueous solutions of T. latifolia root diffusates were sterilized by vacuum fi ltration through the fi lters with 0.2-micron pore diameter. The experimental samples contained cattail secretions, sterile water, and cultures of E. rhusiopathiae or L. interrogans. The same amount of sterile water, as in the experimental samples, was used for the purpose of control, and the same quantity of microbial cultures was added in it. After exposure, the density of cells in the experimental and control samples was determined. Results. Root diffusates of T. latifolia caused an increase in cell density in the populations of E. rhusiopathiae throughout the whole range of the studied dilutions (1:10–1:10000). In the populations of the 6 studied serological variants of L. interrogans spirochetes (pomona, grippotyphosa, copenhageni, kabura, tarassovi, canicola), the action of broadleaf cattail root diffusates caused the decrease in cell density. A stimulatory effect was marked in the experimental samples of the pollonica serological variant of leptospira. Conclusions. The populations of E. rhusiopathiae and L. interrogans pathogenic microorganisms respond to the allelopathic effect of Thypha latifolia by changing the cell density. The obtained results provide the background to assume that broadleaf cattail thickets create favorable conditions for the existence of E. rhusiopathiae pathogen bacteria. The reduced cell density of L. interrogans in the experimental samples compared to the control samples observed under the infl uence of T. latifolia root diffusates suggests that reservoirs with broadleaf cattail thickets are marked by the unfavorable conditions for the existence of pathogenic leptospira (except L. pollonica).

Pengaruh Lama Pengasinan Terhadap Kadar Protein Putih Telur Itik

2014 ◽  
Vol 1 (1) ◽  
pp. 36 ◽  
Author(s):  
Siti Fatimah ◽  
Muji Rahayu ◽  
Siti Aminah
Keyword(s):  
Protein Level ◽  
Egg White ◽  
Special Treatment ◽  
Egg White Protein ◽  
Protein Levels ◽  
Duck Egg ◽  
Egg Period ◽  
Graph Presentation ◽  
And Control ◽  
The Impact

Background : Egg  is one of the animal protein source, which has delicious taste, easy to digest and highly nutritious. Besides its affordable price, its supply availability is unquestionable as well. However, due to its short storability, it requires special treatment, such as preserving, to store it for long period. One way to preserve the egg is by pickling egg, which generally requires seven to ten days of marinating. During the process of marinating, there will be a visual change of egg white and yolk. Their structures  will be more solid (the occurrence of thickening process) because salinization will lead to protein denaturalization. Consequently, it has an influence as well towards the content of egg white protein of duck egg. This study is aimed to explore the impact of various time of pickling egg towards egg white protein of duck egg. Method  : The study where takes place in a laboratories, is a true experimental study for the reason that the researcher must provide intervention, hence all of potentially confounding variables are manageable. Samples that had been used in this study are duck eggs which were bought from North Brebes. This study is expected to generate data from four various time of pickling egg and control (no treatment). Since there are four samples, accordingly the number of data resulted are twenty. The resulted data will be descriptively presented in table, graph, presentation, and narration. Result  : Protein level examination within duck white egg shows changes  in protein levels that occurs in every variation of pickling egg time, where the average results of the assay of duck egg white protein is 14.94% without treatment (control), in five days of pickling time is 13.68%, in seven days of pickling time is 13.29%, in nine days of pickling time is 12.87% and eleven days of pickling time is 12.78%. Conclusion  : There is a significant impact among the period of pickling time to the protein level degradation of duck white egg. Keywords : Duck egg, period of pickling time, level protein of duck white egg.

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