scholarly journals Research the Integration of Geodetic and Geotechnical Methods in Monitoring the Horizontal Displacement of Diaphragm Walls

2021 ◽  
Vol 1 (2) ◽  
Author(s):  
Quoc Khanh PHAM ◽  
Ngoc Dong TRAN ◽  
Thi Kim Thanh NGUYEN ◽  
Van Chung PHAM
Keyword(s):  
Horizontal Displacement ◽  
High Accuracy ◽  
Observation Point ◽  
Ho Chi Minh City ◽  
Soft Ground ◽  
Rock Layer ◽  
Good Efficiency ◽  
Center Point ◽  
Diaphragm Walls ◽  
Observation Results

This article investigates the integration of geodetic and geotechnical methods for monitoringthe horizontal displacement of diaphragm walls. The results show that when the horizontal displacementis measured by the geotechnical method using an inclinometer sensor, the center point at the bottom ofthe guide pipe is usually chosen to be the origin to calculate displacements of the upper points. However,it is challenging to survey the bottom point for checking its stability directly. If this bottom point moves,the observation results will be incorrect. Thus, the guide pipe must be installed in the stable rock layer.But in the soft ground, this rock layer locates more deeply than the diaphragm walls, so the guide pipecannot be laid out at the required location. Geodetic methods can directly observe the displacement of thecenter point on the top of the guide pipe with absolute displacement values at high accuracy. Because thedisplacements of observation points are determined at stable benchmarks, these values are considered thepipe's displacement. Thus, an integrated solution allows the center point on the top of the pipe to be theorigin to calculate the displacements of different points located inside the diaphragm wall. Then, thecalculated values are calibrated back to the inclinometer observed values to achieve highly reliabledisplacement, which reflects the moving of diaphragm walls. An experiment integrating the geodetic andgeotechnical methods is conducted with an observation point at a depth of 20 meters at a construction sitein Ho Chi Minh city. The deviations of the top point that are observed by the two methods are -4.37millimeters and -3.69 millimeters on the X-axis and the Y-axis, respectively. The corrected observedresults prove that the integrated solution has a good efficiency in monitoring the horizontal displacementof diaphragm walls. The bottom point observed by an inclinometer is unconfident enough to choose to bea reference point.

scholarly journals The Integration of Two Interferometric Radars for Measuring Dynamic Displacement of Bridges

2021 ◽  
Vol 13 (18) ◽  
pp. 3668
Author(s):  
Piotr Olaszek ◽  
Andrzej Świercz ◽  
Francesco Boscagli
Keyword(s):  
Longitudinal Vibration ◽  
Experimental Tests ◽  
Horizontal Displacement ◽  
Vertical Displacement ◽  
High Accuracy ◽  
Vertical Vibration ◽  
Remote Measurement ◽  
Railway Bridges ◽  
Vertical Displacements ◽  
Horizontal Displacements

Measurements of displacements of bridges under dynamic load are particularly difficult in the case of structures where access to the area under the tested structure is impossible. Then, remote measurement methods are preferred, such as interferometric radar. Interferometric radar has high accuracy when measuring displacement in the direction of its target axis. The problems appear when a bridge vibrates in two directions: horizontal (lateral or longitudinal) and vertical. The use of one radar to measure those vibrations may be impossible. This paper presents the application of a set of two interferometric radars to measure vertical vibration and horizontal longitudinal vibration with high accuracy. The method was positively verified by experimental tests on two railway bridges characterized by different levels of horizontal displacement. The accuracy of the radar measurements was tested by the direct measurement of vertical displacements using inductive gauges. In conclusion, in the case of vertical displacement measurements using one interferometric radar, the influence of horizontal displacements should be excluded. In the case of locating radars at the area of bridge supports, it is necessary to either use a set of two radars or first investigate the magnitude of possible horizontal displacements in relation to vertical displacements.

Study on Horizontal Displacement of Alluvial Flat Soft Ground under Embankment

2012 ◽  
Vol 178-181 ◽  
pp. 1484-1487 ◽  
Author(s):  
Xiao Mou Wang ◽  
Huai Yu Yuan ◽  
Lin Wang
Keyword(s):  
Failure Mode ◽  
Yellow River ◽  
Horizontal Displacement ◽  
Henan Province ◽  
Soft Ground ◽  
Construction Time ◽  
Deep Layers ◽  
Ground Types ◽  
Horizontal Displacements

There are three soft ground types in the joint highway of Jiaozuo-Gongyi Yellow River bridge in Henan province: shallow, sandwich and deep layers. By analyzing the observation date, the horizontal displacement characteristics of alluvial flat soft ground under embankment are studied. The settlement is the dominant deformation in construction time, but the mainly factor that controls construction speed is horizontal displacement of the weakest layer. The failure mode of sandwich and shallow type grounds is different to the circular one in deep type ground, so the translation mode is put forward. Due to the uniform in thickness and spaces of alluvial flat soft ground, the horizontal displacements are quite different at both sides of subgrade.

Analysis of Mechanical Behavior of Subway Tunnel Constructed by Cover and Cut Reverse Method

2012 ◽  
Vol 446-449 ◽  
pp. 3623-3627
Author(s):  
Tie Cheng Wang ◽  
Yang Gao ◽  
Hai Long Zhao
Keyword(s):  
Bending Moment ◽  
Horizontal Displacement ◽  
Internal Force ◽  
Surrounding Rock ◽  
Diaphragm Wall ◽  
Tunnel Construction ◽  
Construction Process ◽  
Subway Tunnel ◽  
Diaphragm Walls ◽  
Reverse Method

In the paper, not only the internal force and displacement of structure during subway tunnel construction with cover and cut reverse method, but also the displacement field and stress field of surrounding rock are analysed. From the numerical calculation it is shown that the bending moment of diaphragm wall is affected seriously by the distribution and value of the stiffness of horizontal support; the excavation phase of the soil of the second floor underground is the key phase of the construction process because the internal force of structure has large increase; the value of surface settlement, horizontal displacement of diaphragm wall, differential settlement between middle pillar and diaphragm walls all meet the requirements, so the construction is safe and the surrounding buildings are affected slightly.

Dynamic response of axially loaded end-bearing rectangular closed diaphragm walls

2020 ◽  
Vol 75 (7) ◽  
pp. 621-636
Author(s):  
Geng Cao ◽  
Ming-xing Zhu ◽  
Wei-Ming Gong ◽  
Kai-yu Jiang ◽  
Bo-Chen Wang
Keyword(s):  
Cross Sections ◽  
Horizontal Displacement ◽  
Width Ratio ◽  
Soil Core ◽  
Horizontal Distance ◽  
Soil System ◽  
Soil Medium ◽  
Shaft Resistance ◽  
Diaphragm Walls ◽  
Continuous Displacement

AbstractThis paper presents an approximate analytical solution for the vertical dynamic impedance and shaft resistance of rectangular closed diaphragm walls (RCDWs) embedded in a homogeneous soil medium and resting on rock base. The vertical continuous displacement model for the steady-state response of RCDWs is proposed to ensure proper RCDWs-soil contact and satisfy the boundary condition of soil at infinite horizontal distance. The soil horizontal displacement is neglected and the effect is indirectly taken into account by the modification of soil modulus. The functional of system potential and kinetic energies is established via the soil and RCDWs displacement functions. The governing equations of the system and the relevant conditions are obtained and the vertical shaft resistance of RCDWs is established by employing Hamilton’s variational principle for RCDWs-soil system and thin layer element, respectively. Some representative numerical examples are presented to portray the influences of soil core ratio, height–width ratio, diaphragm wall-soil stiffness ratio, and aspect ratio of RCDWs cross sections on the dynamic impedances and stiffness of the shaft resistance.

scholarly journals POTENSI KETERSEDIAAN AIR TANAH DI DESA LIMO KECAMATAN SALIMPAUNG KABUPATEN TANAH DATAR - SUMATERA BARAT

2011 ◽  
Vol 9 (1) ◽  
Author(s):  
Wahyu Garinas
Keyword(s):  
Water Resources ◽  
Ground Water ◽  
Water Potential ◽  
Hard Rock ◽  
Observation Point ◽  
The Other ◽  
Rock Layer ◽  
The North ◽  
Potential Map ◽  
Water Layers

Ground water potential map showed that the Salimpaung in Tanah Datar District has very low water resources potential. Deep and shallow water resources were found in some places and in a limited area.Interpretation of imaging resistivity showed that water resources potential lies in P1 and P2 layers. This layers were found in 90 to 150 meters to the south of the mosque. The potential layer was found between 10 to 30 meter depth and thickness between 5 to 25 meter and lies in observation point between 50 – 125 meter. Water resources at layer P1, P2, P3 and P4 has medium to low potential and the water layers was interpreted as water trap above the rock layer. The other water resources potential were found at P5, P6 and P7, at 90 – 150 meter to the north of the mosque. The potensial aquifer lies beneath hard rock at depth 40 to 60 meter.

scholarly journals Evaluation of Deformation of Adjacent Buildings With Different Foundation Types Caused by Foundation Pit Excavation Under Combined Support of Isolation Pile and Diaphragm Wall

2021 ◽  
Author(s):  
Shaokun Ma ◽  
Fapai Tian ◽  
Zhen Huang ◽  
Hu Lu ◽  
Xiaoxi Fu ◽  
...  
Keyword(s):  
Pile Foundation ◽  
Horizontal Displacement ◽  
Diaphragm Wall ◽  
Deep Foundation ◽  
Foundation Pit ◽  
Deep Foundation Pit ◽  
Maximum Settlement ◽  
Deceleration Rate ◽  
Different Types ◽  
Diaphragm Walls

Abstract The process of excavation and unloading of a deep subway foundation pit will cause deformation of the surrounding buildings. There are significant differences in building deformation due to different methods of supporting the foundation pit and building foundation forms. This study takes the deep foundation pit project of the station as an example to investigate this difference. A three-dimensional numerical finite element model of a deep foundation pit has been established that considers different types of building foundations (independent foundation, box foundation, and pile foundation). The sensitivity of the two supporting methods of the diaphragm wall and the combined support of isolation pile and diaphragm wall regarding the maximum settlement value of the building, the horizontal inclination value, the slope angle, and the foundation angular distortions were analyzed. Finally, the sensitivity of the length of the isolated pile to the maximum settlement value and the horizontal displacement value of different types of building foundations are discussed. The results show that the combined support method of isolation piles and diaphragm walls has the highest supporting efficiency (93.5% of independent foundations and 42.3% of box foundations) for angular distortions of shallow foundation buildings. The efficiency of pile foundation support is the lowest (31.4%). For the combined support method of isolation piles and diaphragm walls, the maximum settlement value, and the value of horizontal displacement of the building will decrease with increasing the length of isolation pile. When the depth of isolation pile is greater than 24 m, the settlement deceleration rate of the independent foundation and the pile foundation slows down; when the depth of isolation pile is greater than 27 m, the settlement deceleration rate of the box foundation will slow down, and the deceleration rate of the horizontal displacement of the independent foundation and box foundation will slow down.

scholarly journals Design and construction of a deep excavation in soft soils adjacent to the Shanghai Metro tunnels

2003 ◽  
Vol 40 (5) ◽  
pp. 933-948 ◽  
Author(s):  
Z F Hu ◽  
Z Q Yue ◽  
J Zhou ◽  
L G Tham
Keyword(s):  
Ground Improvement ◽  
Soft Soil ◽  
Soft Clay ◽  
Theoretical Method ◽  
Horizontal Displacement ◽  
Deep Excavation ◽  
Construction Methods ◽  
Diaphragm Walls ◽  
Shanghai Metro ◽  
Design And Construction

This paper presents the design and construction of a deep excavation for building foundations in saturated soil. This deep excavation was of particular interest because it was located above and beside the Shanghai Metro tunnels. The twin Shanghai Metro tunnels had to be in full operation during the deep excavation. Potential large deformation of the twin tunnels was one of the main concerns during the design and construction for the deep excavation. The paper discusses in detail the criteria and measures for controlling the soil and tunnel deformation. The measures included cast-in-place concrete diaphragm walls with bracing structural members, pumping consolidation, cement–soil mix pile systems, and rational excavation procedures. A simplified theoretical method was proposed to estimate the increment in undrained shear strength in a soft clay layer due to pumping consolidation. Furthermore, conventional finite element methods were used to predict the soil vertical and horizontal displacements induced by the excavation. Using the design and construction methods discussed in the paper, the settlement and horizontal displacement of the tunnels were successfully controlled within 5.0 mm and 9.0 mm, respectively. The curvature of longitudinal deformation curve of the tunnels was less than 1/15 000. The horizontal displacement of the braced diaphragm walls was less than 0.12% of the total excavation depth. Key words: Metro tunnels, saturated soft soil, deep excavation, design, construction, ground improvement, case studies.

scholarly journals CoLiTec software - detection of the near-zero apparent motion

2016 ◽  
Vol 12 (S325) ◽  
pp. 349-352 ◽  
Author(s):  
Sergii V. Khlamov ◽  
Vadym E. Savanevych ◽  
Olexandr B. Briukhovetskyi ◽  
Artem V. Pohorelov
Keyword(s):  
Big Data ◽  
Comparative Analysis ◽  
Moving Objects ◽  
High Efficiency ◽  
High Accuracy ◽  
Wide Field ◽  
Positional Accuracy ◽  
Moving Objects Detection ◽  
Objects Detection ◽  
Observation Results

AbstractIn this article we described CoLiTec software for full automated frames processing. CoLiTec software allows processing the Big Data of observation results as well as processing of data that is continuously formed during observation. The scope of solving tasks includes frames brightness equalization, moving objects detection, astrometry, photometry, etc. Along with the high efficiency of Big Data processing CoLiTec software also ensures high accuracy of data measurements. A comparative analysis of the functional characteristics and positional accuracy was performed between CoLiTec and Astrometrica software. The benefits of CoLiTec used with wide field and low quality frames were observed. The efficiency of the CoLiTec software was proved by about 700.000 observations and over 1.500 preliminary discoveries.

Pile Response Analysis with Unloading Abutment on Soft Ground and Pile Supported Reinforced Embankment Foundation

2014 ◽  
Vol 1065-1069 ◽  
pp. 840-843
Author(s):  
Rong Yao ◽  
Meng Yun Mao ◽  
Yun Que
Keyword(s):  
Finite Element ◽  
Axial Force ◽  
Bending Moment ◽  
Horizontal Displacement ◽  
Response Analysis ◽  
Soft Ground ◽  
Finite Element Software ◽  
Pile Response

There ware numeral analysis by ABAQUS finite element software to discover the pile’s status with unloading abutment in soft ground, three model were built, first model was unloading abutment and pile supported reinforced embankment, second model was only unloading abutment, third model was only pile supported reinforced embankment, the piles horizontal displacement, axial force and bending moment were discussed; the results show that the piles horizontal displacement with pile supported reinforced are smaller than the others models, pile axial force in three model are little difference.

Sign in / Sign up

Export Citation Format

Share Document