scholarly journals Full-Scale Field Test on Construction Mechanical Behaviors of Retaining Structure Enhanced with Soil Nails and Prestressed Anchors

2021 ◽  
Vol 11 (17) ◽  
pp. 7928
Author(s):  
Hui Wang ◽  
Jianhua Cheng ◽  
Hujun Li ◽  
Zhilin Dun ◽  
Baoquan Cheng
Keyword(s):  
Field Test ◽  
Working Conditions ◽  
Horizontal Displacement ◽  
Displacement Current ◽  
In Situ Tests ◽  
External Disturbances ◽  
Time Curve ◽  
Soil Nails ◽  
Prestressing Force ◽  
Main Factor

Soil nailing combined with prestressed anchors has a good workability and is relatively cheap in constraining the horizontal displacement. Current research on the technique, whether theoretical analyses, numerical simulations, or model tests, was conducted under ideal working conditions. However, in fact, external disturbances, such as tensioning-lagging of the anchor, are very common and play an important role on stress and displacement. Therefore, it is of great significance to carry out a field test considering the effects of external disturbances, which can obtain real and reliable data through real-time monitoring. In this paper, the impacts of the construction conditions on practical engineering are discussed based on in situ tests, and some reasonable suggestions for the upgrading of misbehaviors in the current construction situation are put forward. In particular, the influence features of soil predisturbance, excessive excavation, unloading on the surface of edges, tensioning-lagging of the anchor, and continuous rainfall on the stress–time curve of soil nails under practical working conditions are analyzed. Behaviors of three different retaining structures enhanced with (i) soil nails; (ii) soil nails and prestressed anchors without unbonded parts; and (iii) soil nails and prestressed anchors with a 2.5 m unbonded part were monitored during staged excavation to investigate the influences of (i) the prestressing force and (ii) the unbonded part of the prestressed anchors on the performance of the entire retaining system. Results show that (i) the prestressing force is the main factor affecting the stress and deformation of the composite retaining system, which is consistent with the existing literature; (ii) the variation of the magnitude and distribution of the soil nail force responding to the anchor prestressing force, however, showed no systematic trend; and (iii) the unbonded part of anchors, which was validated to be the main factor affecting the structural stability in dense materials in the existing literature, is found to have a minor influence in loose fill materials used in this study.

scholarly journals Full-Scale Field Test On Retaining Structure Enhanced With Soil Nails And Prestressed Anchors

2021 ◽  
Author(s):  
Hui Wang ◽  
Jian-hua Cheng ◽  
Yuan-cheng Guo
Keyword(s):  
Rational Design ◽  
Horizontal Displacement ◽  
In Situ Tests ◽  
Foundation Pit ◽  
Soil Nails ◽  
Soil Nail ◽  
Retaining Structure ◽  
Prestressing Force ◽  
Materials Used ◽  
Unbonded Length

Abstract Retaining structure enhanced with soil nails and prestressed anchors is found good at constraining the horizontal displacement and therefore ensuring the stability of the foundation pit during excavation. Based on these advantages, such retaining structure is widely used in foundation excavation practice. This paper presents results of a series of in-situ tests conducted to investigate the mechanical behaviors of retaining structure enhanced with soil nails and prestressed anchors. Behaviors of three different retaining structures enhanced with i) soil-nails; ii) soil-nails and prestressed anchors without unbonded part; iii) soil-nails and prestressed anchors with a 2.5m unbonded length, were monitored during staged excavation to investigate the influences of i) the prestressing force and ii) unbonded length of the prestressed anchors on the performance of the entire retaining system. It was found that the affecting the stress and deformation of composite retaining system, which is in agreement with the other published results in the literature. The variation of the magnitude and distribution of soil nail force responding to the anchor prestressing force however showed no systematic trend. The unbonded length of anchors, which is suggested to be the main factor affecting the structural stability in dense materials in the literature, is found to have little influence in loose fill materials used in this study. Studies presented in this paper are useful for the rational design and serviceability analysis of the composite soil-nailed retaining structure enhanced with prestressed anchors.

scholarly journals Analysis of Vehicle Collision on an Assembled Anti-Collision Guardrail

Sensors ◽  
2021 ◽  
Vol 21 (15) ◽  
pp. 5152
Author(s):  
Juncheng Yao ◽  
Bo Wang ◽  
Yujie Hou ◽  
Liang Huang
Keyword(s):  
Working Conditions ◽  
Traffic Accidents ◽  
Analysis Software ◽  
Time Curve ◽  
Vehicle Collisions ◽  
Moving Vehicle ◽  
Vehicle Collision ◽  
New Type ◽  
Main Girder ◽  
Protective Performance

Traffic accidents such as vehicle collisions with bridge guardrails occur frequently. These accidents cause damage to the driver and the vehicle as well as the bridge. A new type of assembled anti-collision guardrail is proposed in this study. LS-DYNA is a nonlinear display dynamic analysis software used to evaluate the safety of a new type of assembled anti-collision guardrail. A specific, numerically analyzed model of vehicle–guardrail collision is established using LS-DYNA. The energy distribution–time curve of the vehicle collision process is obtained. After comparison with measured data from the vehicle collision test, the model of vehicle–guardrail collision is verified as being correct. Based on this, we analyze the process of a vehicle collision on the assembled anti-collision guardrail. The result shows that the assembled anti-collision guardrail proposed in this paper can better change the trajectory of a moving vehicle and can prevent the vehicle from falling off the bridge. From the car body collision results, the assembled anti-collision guardrail for bridges proposed in this paper can reduce vehicle damage and can protect the driver effectively. From the analysis of the main girder stress on the bridge, an anti-collision guardrail installed on an existing bridge will not cause damage to the main girder during a collision. In order to study the influence of the four parameters on the anti-collision effect, we carried out a comparative calculation of multiple working conditions. The results show that the new type of assembled anti-collision guardrail has good protective performance under different working conditions.

Boom System Kinematic Simulation of Truck-Mounted Concrete Pump

2011 ◽  
Vol 201-203 ◽  
pp. 185-188 ◽  
Author(s):  
Xin Xiang Zhou ◽  
Nan Nan Ren ◽  
Shu Jun Guo ◽  
Yan Ling Tang ◽  
Rong Liang Tian
Keyword(s):  
Working Conditions ◽  
Three Dimensional ◽  
Paper Study ◽  
Time Curve ◽  
Kinematic Simulation ◽  
Simulation Process ◽  
Solid Works ◽  
Force Time ◽  
Concrete Pump ◽  
A Company

In this paper, we study the boom of truck-mounted concrete pump from a company. After analyzing, we determine that the four booms extending horizontally is the most dangerous working conditions. We use the software Solid Works to design three-dimensional entity. With the help of Cosmos Motion which is a part of Solid Works, realizing the kinematic simulation. This paper study and analyze the problems during the simulation process, and collect a series of curves of kinematic simulation, mainly including the place-time curve, velocity-time curve and force-time curve, and analyze these curves detailedly.

Study on Composite Soil Nailing Wall in Soft Soil Area of Complex Condition with Emphasis on Analysis by Finite Element Analysis

2012 ◽  
Vol 174-177 ◽  
pp. 2020-2023 ◽  
Author(s):  
Bing Wang
Keyword(s):  
Finite Element ◽  
Soft Soil ◽  
Horizontal Displacement ◽  
Deep Foundation ◽  
Circular Area ◽  
Foundation Pit ◽  
Soil Nails ◽  
Deep Foundation Pit ◽  
Soft Soil Area ◽  
Soil Area

Based on a typical projects, the horizontal displacement in depth, horizontal displacement and vertical subsidence of pile top, and settlements of surrounding buildings are monitored with the process on digging of deep foundation pit. The study on digging process of foundation pit is analyzed by using finite element software. Using mapped meshing method, from mixing the pile near the semi-circular area (radius = 50m), the meshing appropriate encryption in order to improve the accuracy of the external semi-circular area (radius = 65m) mesh is less appropriate sparse.Layer by layer to kill the layers of the soil unit and activate the soil nails (spring element), the simulated excavation and synchronization of soil nails construction.Verify the arc form of failure surface in side of deep foundation pit in soft soil area. Which is valuable for reference to similar structure engineering of foundation pit.

scholarly journals Active Model-Based Hysteresis Compensation and Tracking Control of Pneumatic Artificial Muscle

Sensors ◽  
2022 ◽  
Vol 22 (1) ◽  
pp. 364
Author(s):  
Yanding Qin ◽  
Haoqi Zhang ◽  
Xiangyu Wang ◽  
Jianda Han
Keyword(s):  
Unscented Kalman Filter ◽  
Reference Model ◽  
Artificial Muscle ◽  
Pneumatic Artificial Muscle ◽  
Tracking Accuracy ◽  
External Disturbances ◽  
Hysteresis Compensation ◽  
Modeling Errors ◽  
Active Modeling ◽  
Main Factor

The hysteretic nonlinearity of pneumatic artificial muscle (PAM) is the main factor that degrades its tracking accuracy. This paper proposes an efficient hysteresis compensation method based on the active modeling control (AMC). Firstly, the Bouc–Wen model is adopted as the reference model to describe the hysteresis of the PAM. Secondly, the modeling errors are introduced into the reference model, and the unscented Kalman filter is used to estimate the state of the system and the modeling errors. Finally, a hysteresis compensation strategy is designed based on AMC. The compensation performances of the nominal controller with without AMC were experimentally tested on a PAM. The experimental results show that the proposed controller is more robust when tracking different types of trajectories. In the transient, both the overshoot and oscillation can be successfully attenuated, and fast convergence is achieved. In the steady-state, the proposed controller is more robust against external disturbances and measurement noise. The proposed controller is effective and robust in hysteresis compensation, thus improving the tracking performance of the PAM.

Numerical Simulation and Experimental Research of Icicles under the Single Point of Blasting in the Yellow River

2014 ◽  
Vol 501-504 ◽  
pp. 2020-2025 ◽  
Author(s):  
Wen Yuan Meng ◽  
Guan Chao Xu ◽  
Jia Qing Li ◽  
Guan Chun Xu ◽  
Jun Wei Guo ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Field Test ◽  
Working Conditions ◽  
Experimental Research ◽  
Calculation Result ◽  
Yellow River ◽  
Single Point ◽  
The Yellow River ◽  
Water Medium ◽  
Different Thickness

Blasting model of ice is established by ANSYS-LSDYNA in this paper. By using LS-PREPOST, the author analyzes the broken volume or diameter of ice in different working conditions, including the buried depth of explosive, the load and the thickness of ice. ORIGN drawing software is used to analyze the most suitable blasting location with different thickness of ice. The result shows that when the thickness is between 20cm and 60cm, the best blasting coefficient of water-medium ice is K=R/ H =0.5~1. It also shows that the explosive effect will be better when it is exploded under ice layer than in the middle or at the surface of ice layer. Calculation result and field test align fairly well. By simulating blasting parameter in different working conditions, ice prevention database is built, providing references for designers to develop a series of shaped into ice equipments. It also has important practical meaning to use various equipments to prevent and treat ice disasters of the Yellow River.

The Analysis of Long Spiral Drilling Hole’s Deformation with Finite Element

2010 ◽  
Vol 168-170 ◽  
pp. 206-210
Author(s):  
Xiu Shao Zhao ◽  
Lin Li Mo ◽  
Da Xin Geng
Keyword(s):  
Finite Element ◽  
Groundwater Level ◽  
High Strength ◽  
Horizontal Displacement ◽  
Element Model ◽  
Soil Strength ◽  
Drilling Depth ◽  
3D Finite Element ◽  
Spiral Blade ◽  
Main Factor

The long spiral CFG pile construction often causes crack while in saturated slit. 3D finite element model is carried out, and the deformation of drilling hole is analyzed. The deformation’s factors are emphtically discussed such as drilling depth, dumped-soil load, soil strength, groundwater level etc. The results show that uneven settlement and horizontal displacement are relatively small while silt has high strength. The reduced soil strength is the main factor of drilling holes’ deformation, which causes serious hole shrinkage and the soil is brought to surface with spiral blade, and then causes “excessive dumping” and soil cracking.

Application of Prestressed Anchor Composite Soil Nail Wall in Deep Foundation Pit Engineering at Lanzhou Region

2014 ◽  
Vol 1030-1032 ◽  
pp. 714-718
Author(s):  
Hui Tao
Keyword(s):  
Soil Layer ◽  
Horizontal Displacement ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Soil Nails ◽  
Change Rate ◽  
Deep Foundation Pit ◽  
Soil Nail ◽  
Support Engineering ◽  
Prestressed Anchor

The paper introduces the application of prestressed anchors and soil nails support system in complex soil layer deep foundation pit engineering at Lanzhou region based on the deep foundation pit engineering in Gansu Provincial Hospital of TCM as the background and discusses its key technology. The effect shows that scheme of the design of foundation pit support engineering is reasonable and effective.The engineering meets requirements of design and environment.The monitoring results show that prestressed anchors can control the horizontal displacement and the change rate of slope′s vertical settlement effectively. The experience of engineering is significance for similar engineerings at Lanzhou region.

scholarly journals Optimization of Stope Structure Parameters Based on the Mined Orebody at the Meishan Iron Mine

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Mingzhi Sun ◽  
Fengyu Ren ◽  
Hangxing Ding
Keyword(s):  
Field Test ◽  
Structural Parameters ◽  
Reliable Data ◽  
Structure Parameters ◽  
In Situ Tests ◽  
Sublevel Caving ◽  
Iron Mine ◽  
The Difference

Based on the engineering background of the Meishan iron mine with sublevel caving (SLC) method, in this work, we adopted the method for identifying the shape of mined orebody (the original location in blasted slice), which analyzed and determined reasonable stope structure parameters. In the field test, the markers were arranged in the blasted slice, the mined orebody was measured by in situ tests, and reliable data were achieved. The shape of the mined orebody was obtained through this test when the width of drift was 6 m. The mined orebody’s shape was compared with the shape of the isolated extraction zone (IEZ), and the difference increased with increasing height. When the stope structural parameters were determined by the mined orebody, the larger the sublevel height was, the smaller the error was, which was compared with the method using ellipsoid arrangement theory to determine the stope structural parameters. Finally, the reasonable stope structure parameters were optimized. The sublevel height was 22 m, and the drift spacing was 20 m.

Analysis on Strength, Stiffness and Stability for Shippment Structure of Hull Subsection

2012 ◽  
Vol 166-169 ◽  
pp. 1019-1022
Author(s):  
Qing Dun Zeng ◽  
Meng Hua Qiao
Keyword(s):  
Finite Element ◽  
Working Conditions ◽  
Theoretical Foundation ◽  
Horizontal Displacement ◽  
Internal Force ◽  
National Standards ◽  
Solid Model ◽  
Safety Requirements ◽  
Finite Element Software ◽  
Actual Working

In allusion to the safety problems of the shippment structure of hull subsection at area B in a Shipyard Co., Ltd., Guangdong, in this paper, a solid model for a proposed shippment structure of hull subsection was established by using a finite element software ANSYS which is a common software, the internal force (stress), deformation and stability of components under various actual working conditions were calculated, and then the checks of strength, stiffness and stability were performed on the basis of the national regulations. The results show that both strength and stability can meet the safety requirements of operation, but stiffness is insufficient, because the horizontal displacement of steel pillars in shippment structure oversteps the specified value of the national standards of China. The conclusion provides a theoretical foundation for the safety use of shippment structure of hull subsection and the optimization and improvement of the structure.

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