A Simplified Numerical Method to Determine the Loads Acting on the Cutterhead of a Compound Shield

2011 ◽  
Vol 199-200 ◽  
pp. 25-31
Author(s):  
Fei Jiang He ◽  
Qiang Zhang ◽  
Zong Xi Cai
Keyword(s):  
Large Scale ◽  
Earth Pressure ◽  
Coupled System ◽  
Governing Equations ◽  
The Earth ◽  
Nonlinear Contact ◽  
Total Thrust ◽  
Set Up ◽  
The Relationship ◽  
Fully Coupled

In order to determine the loads acting on the cutterhead of a compound shield, this paper aims at the large-scale and fully coupled system of the excavation face. Firstly, a new model is proposed to calculate the loads acting on a single cutter, in which the earth pressure of the chamber is taken into consideration. Then, by transforming the large-scale nonlinear contact problem into a smaller one, we set up the governing equations only including the penetration depth of cutters in the approach of the sub-structure condensation, to calculate the loads acting on the cutterhead. Finally, the relationship between the penetration per revolution and the total thrust and total torque acting on the cutters of the cutterhead of a compound shield is investigated.

A Double Inequality Method for Calculate the Loading Capacity of a Sheet Pile DIMSP

2012 ◽  
Vol 268-270 ◽  
pp. 725-728
Author(s):  
Yi Huan Xie
Keyword(s):  
Retaining Wall ◽  
Engineering Application ◽  
Earth Pressure ◽  
Plasticity Condition ◽  
Loading Capacity ◽  
Sheet Pile ◽  
Double Inequality ◽  
The Earth ◽  
Additional Correction ◽  
Set Up

The passive earth pressure on the both sides of a sheet pile retaining wall is owing to plasticity bounded, a fact that affects the horizontal loading capacity of the wall. In order to find out a method, that the loading capacity of the wall can be analytically calculated and the mentioned constrain could be token into account, the paper set up a DIMSP model, which consists of mechanics equilibrium principle including two inequalities for the plasticity condition of earth pressure. The deduced solution of the model is capable of calculating the bearing capacity, and possesses the advantages of no additional correction of the cut in depth of the wall. Further more the continuity of earth pressure distribution is ensured by this model, an adjustment of the earth pressure figure is also without difficulty possible. For engineering application some graphics are given, the cut in depth of the wall can be read from them conveniently.

scholarly journals Correction of Earth Pressure and Analysis of Deformation for Double-Row Piles in Foundation Excavation in Changchun of China

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Yijun Zhou ◽  
Aijun Yao ◽  
Haobo Li ◽  
Xuan Zheng
Keyword(s):  
Physical Model ◽  
Model Test ◽  
Large Scale ◽  
Similarity Theory ◽  
Earth Pressure ◽  
Physical Model Test ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Double Row ◽  
The Earth

In order to study the earth pressure and the deformation behavior of the double-row piles in foundation excavation, a large-scale physical model test was introduced to simulate deformation of double-row piles in foundation excavation based on the principle of similarity theory in this paper. Represented by the deep foundation pit engineering of Changchun, the strain and the displacement of the double-row piles and the earth pressure are calculated by the above-mentioned physical model test. Then a numerical simulation has been carried out to validate practicability of the physical model test. The results show that the strain and the displacement of the front-row piles are larger than the back-row piles. The earth pressure of the front-row piles appears to be “right convex,” correcting the specification of the earth pressure and putting forward the coefficient of β. The results in this paper may provide constructive reference for practical engineering.

scholarly journals MODELLING WAVE-INDUCED RESIDUAL PORE PRESSURE AND DEFORMATION OF SAND FOUNDATIONS UNDERNEATH CAISSON BREAKWATERS

2012 ◽  
Vol 1 (33) ◽  
pp. 56
Author(s):  
Hisham El Safti ◽  
Matthias Kudella ◽  
Hocine Oumeraci
Keyword(s):  
Large Scale ◽  
Pore Fluid ◽  
Model Verification ◽  
Computational Time ◽  
Governing Equations ◽  
Surface Plasticity ◽  
Preliminary Validation ◽  
Fluid Convection ◽  
Wave Induced ◽  
Fully Coupled

A finite volume model is developed for modelling the behaviour of the seabed underneath monolithic breakwaters. The fully coupled and fully dynamic Biot’s governing equations are solved in a segregated approach. Two simplifications to the governing equations are presented and tested: (i) the pore fluid acceleration is completely neglected (the u-p approximation) and (ii) only the convective part is neglected. It is found that neglecting the pore fluid convection does not reduce the computational time for the presented model. Verification of the model results with the analytical solution of the quasi-static equations is presented. A multi-yield surface plasticity model is implemented in the model to simulate the foundation behaviour under cyclic loads. Preliminary validation of the model with large-scale physical model data is presented.

scholarly journals Unified particle method with application to the 2013 Huangping landslides and tsunamis event of China

2018 ◽  
Vol 53 ◽  
pp. 03018
Author(s):  
Quan Jiang ◽  
Xi-liang Chen ◽  
Xiang-dong Qiu
Keyword(s):  
Large Scale ◽  
Particle Method ◽  
High Accuracy ◽  
Governing Equations ◽  
Wave Generator ◽  
Lagrangian Form ◽  
Verification Test ◽  
Simulation Results ◽  
Impulse Waves ◽  
The Relationship

In this study, a unified particle method is presented to simulate the fluid-solid coupling problem in broad range of scales such as landslide and tsunamis. First, a general overview of the method is addressed, and the governing equations are solved in a Lagrangian form. Second, the method is used to simulate the Scott Russell wave generator experiment containing simple fluid-solid coupling, and the relationship between the simulation results and the experimental results is analyzed to verify the validity of the model. Then, the method is applied to the 2D processes simulation of Huangping landslide generated impulse waves in large scale. The results show that: in the verification test, the wave amplitude error between the simulation and the experimental data is almost 0. In the application case of Huangping landslides and tsunamis, the maximum impulse wave height obtained by the simulation is close to the local observations, which indicates that the method has high accuracy and credibility.

A New Method to Calculate Damage Variable with Unload/Load Response Ratio

2014 ◽  
Vol 1065-1069 ◽  
pp. 2040-2043
Author(s):  
Juan Zhang ◽  
Yuan Zhang ◽  
Ke Qiang He ◽  
Wei Gong Chen
Keyword(s):  
Large Scale ◽  
Damage Mechanics ◽  
Health Assessment ◽  
Damage Variable ◽  
Response Ratio ◽  
Load Response ◽  
Set Up ◽  
The University ◽  
Theory Of Damage ◽  
The Relationship

As an exploration and extension of load/unload response ratio theory, unload/ load response ratio theory (ULRR for short) is introduced firstly, and the relationship between ULRR (Y′) and elastic modulus (E for short) is obtained. Based on the basic theory of damage mechanics,the relationship between ULRR and damage variable (D for short) is set up and analyzed with the relationship between E and D. The unloading and loading experiments on a two-story structure carried out in the University of Naples in Italy are introduced;and calculated damage variable is compared with that calculated by Zhang Langping who put forward Weibull distribution as random distribution function. The results show that damage variable of the structure keep highly consistent with calculations of these two methods. Therefore, the relationship between Y′and D provides a new approach to a health assessment to catastrophic failure of large-scale structures and prediction of engineering.

Model for predicting displacement-dependent lateral earth pressure

2009 ◽  
Vol 46 (8) ◽  
pp. 969-975 ◽  
Author(s):  
Guoxiong Mei ◽  
Qiming Chen ◽  
Linhui Song
Keyword(s):  
Earth Pressure ◽  
The State ◽  
Passive State ◽  
Test Results ◽  
Lateral Earth Pressure ◽  
The Earth ◽  
Proposed Model ◽  
Pressure Changes ◽  
The Relationship ◽  
Good Agreement

A model for predicting displacement-dependent lateral earth pressure was proposed based on an earth pressure – displacement relationship commonly observed in practice. The proposed model is a monotonically increasing and bounded function, with an inflection point at the displacement of s = 0 at which the earth pressure changes from the intermediate active state (the state between active and at-rest) to the intermediate passive state (the state between at-rest and passive). The proposed model can predict the relationship between earth pressure and retaining structure movement for any condition intermediate to the active and passive states, which was verified by the experimental data reported in published literature. The predicted lateral earth pressure coefficients are in good agreement with the test results of model tests reported in the literature.

Interactions between Moisture and Tropical Convection. Part I: The Coevolution of Moisture and Convection

2020 ◽  
Vol 77 (5) ◽  
pp. 1783-1799 ◽  
Author(s):  
Brandon Wolding ◽  
Juliana Dias ◽  
George Kiladis ◽  
Fiaz Ahmed ◽  
Scott W. Powell ◽  
...  
Keyword(s):  
Large Scale ◽  
Climate Models ◽  
Weather Prediction ◽  
Coupled System ◽  
Tropical Convection ◽  
Convective Precipitation ◽  
Precipitation Regime ◽  
Spatiotemporal Scales ◽  
The Relationship ◽  
Joint Evolution

Abstract Realistically representing the multiscale interactions between moisture and tropical convection remains an ongoing challenge for weather prediction and climate models. In this study, we revisit the relationship between precipitation and column saturation fraction (CSF) by investigating their tendencies in CSF–precipitation space using satellite and radar observations, as well as reanalysis. A well-known, roughly exponential increase in precipitation occurs as CSF increases above a “critical point,” which acts as an attractor in CSF–precipitation space. Each movement away from and subsequent return toward the attractor results in a small net change of the coupled system, causing it to evolve in a cyclical fashion around the attractor. This cyclical evolution is characterized by shallow and convective precipitation progressively moistening the environment and strengthening convection, stratiform precipitation progressively weakening convection, and drying in the nonprecipitating and lightly precipitation regime. This behavior is evident across a range of spatiotemporal scales, suggesting that shortcomings in model representation of the joint evolution of convection and large-scale moisture will negatively impact a broad range of spatiotemporal scales. Novel process-level diagnostics indicate that several models, all implementing versions of the Zhang–McFarlane deep convective parameterization, exhibit unrealistic coupling between column moisture and convection.

scholarly journals The large-scale magnetospheric electric field observed by Double Star TC-1

2010 ◽  
Vol 28 (9) ◽  
pp. 1625-1631
Author(s):  
Z. H. He ◽  
Z. X. Liu ◽  
T. Chen ◽  
C. Shen ◽  
X. Li ◽  
...  
Keyword(s):  
Electric Field ◽  
Large Scale ◽  
Ring Current ◽  
Double Star ◽  
Moderate Activity ◽  
Activity Levels ◽  
The Earth ◽  
Average Electric Field ◽  
The Relationship ◽  
Low Activity

Abstract. The relationship between the average structure of the inner magnetospheric large-scale electric field and geomagnetic activity levels has been investigated by Double Star TC-1 data for radial distances ρ between 4.5 RE and 12.5 RE and MLT between 18:00 h and 06:00 h from July to October in 2004 and 2005. The sunward component of the electric field decreases monotonically as ρ increases and approaches zero as the distance off the Earth is greater than 10 RE. The dawn-dusk component is always duskward. It decreases at about 6 RE where the ring current is typically observed to be the strongest and shows strong asymmetry with respect to the magnetic local time. Surprisingly, the average electric field obtained from TC-1 for low activity is almost comparable to that observed during moderate activity, which is always duskward at the magnetotail (8 RE~12 RE).

Reinforcement Mechanism of the Deep Buried Piles by Large Scaled Model Tests

2010 ◽  
Vol 108-111 ◽  
pp. 724-729 ◽  
Author(s):  
Wen Jie Lei ◽  
Yin Gren Zheng ◽  
Ya Kun Song
Keyword(s):  
Design Method ◽  
Earth Pressure ◽  
Scaled Model ◽  
Reinforcement Mechanism ◽  
Testing Tools ◽  
The Earth ◽  
Load Cells ◽  
The Relationship ◽  
Variation Process ◽  
Sliding Force

Series of large scaled model test has been carried out to examine the reinforcement mechanism of deep buried piles. Testing tools including rigid load cells, the earth pressure cells and data collecting systems are employed to measure the anti-thrust received by deep buried piles and the slope thrust of the slope on piles top. On the basis of the variation process of measured data, the time and the location of slide surface in the slope is determined, and the maximal anti-sliding force upward to the piles top could be gained by the data of earth pressure cells. Then the failure form process is analyzed with the anti-sliding length of the piles changed. The relationship between the sliding force received by the piles and that supplied by the slope on piles top is analyzed to supply scientific demonstration for the design method of slope reinforced by the deeply buried piles.

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