Design, construction, and performance of a slurry trench wall next to foundations

1977 ◽  
Vol 14 (3) ◽  
pp. 324-339
Author(s):  
Peter Rosenberg ◽  
G. St.-Arnaud ◽  
N. L. Journeaux ◽  
H. Vallée
Keyword(s):  
Ground Level ◽  
Engineering Problem ◽  
Existing Structures ◽  
Slurry Trench ◽  
Below Ground ◽  
Crack Movement ◽  
And Performance ◽  
The Stability ◽  
Two Stages ◽  
Design Construction

The stability of excavations adjacent to existing structures is an engineering problem and challenge. With the amount of construction increasing many such excavations are being planned and constructed. This paper documents the design, construction, and performance of a tied-back retaining system constructed by the slurry trench method. The system was necessary to retain the sides of a 30-ft (9.1-m) deep cut in glacial till immediately adjacent to the heavily loaded foundations of historically important and settlement sensitive structures. The main structures next to the excavation included the façade of the south transept and the 266-ft (81.1-m) high steeple of St. Jacques Church. Foundation loads imposed by these structures vary from 5.5 to 6.5 tons/ft2 (527–622 kPa)at a depth of 5 ft (1.5 m) below ground level. The slurry trench, up to 50 ft (15.3 m) in depth, approached to within 8 ft (2.44 m) of these foundations. Excavation was in two stages with tiebacks holding the wall at each level. The slurry trench and surrounding structures were instrumented using settlement points, crack movement devices, horizontal measurement points, inclinometers, and load cells. The soil investigation and design methods adopted are described.

Design, Construction and Performance of a Soil-Bentonite Cutoff Wall Constructed in Two Stages

2009 ◽  
pp. 289-289-20 ◽  
Author(s):  
MA Khoury ◽  
PH Fayad ◽  
RS Ladd
Keyword(s):  
Cutoff Wall ◽  
And Performance ◽  
Two Stages ◽  
Design Construction

Design, construction and performance study of a cascade impactor for reducing diesel particulate emission

2009 ◽  
Vol 39 (0) ◽  
Author(s):  
Md Shamim Akhter ◽  
SM Najmul Hoque ◽  
Md Nurun Nabi
Keyword(s):  
Cascade Impactor ◽  
Performance Study ◽  
Particulate Emission ◽  
Diesel Particulate ◽  
And Performance ◽  
Design Construction

scholarly journals Analytical Modeling and Design of Novel Conical Halbach Permanent Magnet Couplings for Underwater Propulsion

2021 ◽  
Vol 9 (3) ◽  
pp. 290
Author(s):  
Yukai Li ◽  
Yuli Hu ◽  
Youguang Guo ◽  
Baowei Song ◽  
Zhaoyong Mao
Keyword(s):  
Permanent Magnet ◽  
Analytical Calculation ◽  
Underwater Propulsion ◽  
Conical Structure ◽  
Torque Analysis ◽  
Dynamic Seal ◽  
And Performance ◽  
The Stability ◽  
Propulsion Unit ◽  
Force Calculation

Permanent magnet couplings can convert a dynamic seal into a static seal, thereby greatly improving the stability of the underwater propulsion unit. In order to make full use of the tail space and improve the transmitted torque capability, a conical Halbach permanent magnet coupling (C-HPMC) is proposed in this paper. The C-HPMC combines multiple cylindrical HPMCs with different sizes into an approximately conical structure. Compared with the conical permanent magnet couplings in our previous work, the novel C-HPMC has better torque performance and is easy to process. The analytical calculation method of transmitted torque of C-HPMC is proposed on the basis of torque calculation of the three common types of HPMCs. The accuracy of the torque calculation of the three HPMCs is verified, and the torque performance of the three HPMCSs of different sizes is compared and discussed. The “optimal type selection” method is proposed and applied in the design of C-HPMC. Finally, on the basis of torque analysis calculation and axial force calculation, a complete flowchart of the design and performance analysis of C-HPMC is described.

Adaptive attitude-tracking control of spacecraft considering on-orbit refuelling

2020 ◽  
pp. 014233122097313
Author(s):  
Yiqi Xu
Keyword(s):  
Tracking Control ◽  
Closed Loop ◽  
Closed Loop System ◽  
Tracking Errors ◽  
Attitude Tracking ◽  
Control Scheme ◽  
Inertia Model ◽  
And Performance ◽  
Attitude Tracking Control ◽  
The Stability

This paper studies the attitude-tracking control problem of spacecraft considering on-orbit refuelling. A time-varying inertia model is developed for spacecraft on-orbit refuelling, which actually includes two processes: fuel in the transfer pipe and fuel in the tank. Based upon the inertia model, an adaptive attitude-tracking controller is derived to guarantee the stability of the resulted closed-loop system, as well as asymptotic convergence of the attitude-tracking errors, despite performing refuelling operations. Finally, numerical simulations illustrate the effectiveness and performance of the proposed control scheme.

scholarly journals EFFECT OF NONCLASSICAL POLARIZATION OF Na+ AND K+ ON THE STABILITY OF SOIL COLLOIDAL PARTICLES IN SUSPENSION

2017 ◽  
Vol 24 (07) ◽  
pp. 1850019
Author(s):  
DING WU-QUAN ◽  
HE JIA-HONG ◽  
WANG LEI ◽  
LIU XIN-MIN ◽  
LI HANG
Keyword(s):  
Negative Pressure ◽  
Colloidal Particles ◽  
Ion Concentration ◽  
Electrostatic Repulsion ◽  
Adjacent Soil ◽  
Net Pressure ◽  
The Stability ◽  
Two Stages ◽  
Soil Colloids ◽  
Total Average

The study of soil colloids is essential because the stability of soil colloidal particles are important processes of interest to researchers in environmental fields. The strong nonclassical polarization of the adsorbed cations (Na[Formula: see text] and K[Formula: see text] decreased the electric field and the electrostatic repulsion between adjacent colloidal particles. The decrease of the absolute values of surface potential was greater for K[Formula: see text] than for Na[Formula: see text]. The lower the concentration of Na[Formula: see text] and K[Formula: see text] in soil colloids, the greater the electrostatic repulsion between adjacent colloidal particles. The net pressure and the electrostatic repulsion was greater for Na[Formula: see text] than for K[Formula: see text] at the same ion concentration. For K[Formula: see text] and Na[Formula: see text] concentrations higher than 50[Formula: see text]mmol L[Formula: see text] or 100 mmol L[Formula: see text], there was a net negative (or attractive) pressure between two adjacent soil particles. The increasing total average aggregation (TAA) rate of soil colloids with increasing Na[Formula: see text] and K[Formula: see text] concentrations exhibited two stages: the growth rates of TAA increased rapidly at first and then increased slowly and eventually almost negligibly. The critical coagulation concentrations of soil colloids in Na[Formula: see text] and K[Formula: see text] were 91.6[Formula: see text]mmol L[Formula: see text] and 47.8[Formula: see text]mmol L[Formula: see text], respectively, and these were similar to the concentrations at the net negative pressure.

Nondestructive Test on Typical Roadway Supports of a Mine via Drilling Core and Ground Penetrating Radar

2011 ◽  
Vol 368-373 ◽  
pp. 2411-2416
Author(s):  
Jian Ping Han ◽  
Hai Peng Liu
Keyword(s):  
Ground Penetrating Radar ◽  
Geological Structure ◽  
Surrounding Rock ◽  
Potential Threat ◽  
Real Performance ◽  
Design Requirements ◽  
And Performance ◽  
The Stability ◽  
Ground Penetrating ◽  
Drilling Core

Temporary or permanent supports are necessary in underground construction for maintaining the stability and limiting the damage of surrounding rock. Due to the uncertainty of geological structure, the specificity of the underground environment as well as other factors, the quality and performance of supporting structure are often difficult to satisfy the design requirements, which not only seriously affects the normal construction and operation of mines but also has the potential threat to the safety of underground production. In order to investigate the influence of the unfavorable geologic environment on supporting concrete and evaluate the real performance of roadway supports of a mine, 17 typical projects were chosen and the strength of supporting concrete was detected by nondestructive drilling core method. The result shows that the strength is widely less than the design value. Furthermore, 4 projects of them were investigated by the ground penetrating radar (GPR) in order to evaluate the feasibility of GPR in the performance investigation of the roadway supports of a mine. The results indicate that ground penetrating radar is capable of measuring the thickness of the support, the distribution of rebars and the defects of the surrounding rock.

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