Buried pipeline responses to ground displacements induced by adjacent static pipe bursting

2013 ◽  
Vol 50 (5) ◽  
pp. 481-492 ◽  
Author(s):  
Jiangwei Shi ◽  
Yu Wang ◽  
Charles W.W. Ng
Keyword(s):  
Urban Areas ◽  
Ground Surface ◽  
Soil Stiffness ◽  
Worked Example ◽  
Bending Strain ◽  
Versus Ratio ◽  
Adjacent Structures ◽  
Pipe Bursting ◽  
Parametric Studies ◽  
Ground Displacements

To minimize disruptions of economic and social activities on the ground surface in urban areas, trenchless techniques such as pipe bursting are often considered for underground pipeline construction, rehabilitation, and renewal of existing utility services. Pipe bursting, however, inevitably induces outward displacements of surrounding soil, and subsequently leads to potential damages to adjacent structures and utilities. This paper carries out finite element (FE) analyses to investigate effects of the static pipe bursting–induced ground displacements on adjacent pipelines. In total 760 FE parametric studies are performed to encompass various combinations of ground settlement profiles, pipe dimensions, material properties, and soil properties that are typical of utility pipelines and pipe bursting in urban areas. The FE parametric results are summarized in a dimensionless plot of relative pipe–soil stiffness versus ratio of maximum pipe curvature to maximum ground curvature, which can be used to directly estimate the maximum pipe bending strain and (or) directly evaluate pipeline responses to adjacent pipe bursting. A worked example is provided to illustrate usage of the dimensionless plot. It is further found that the pipe–soil interaction is similar for pipe bursting and tunneling, and the effects of both pipe bursting and tunneling on adjacent pipelines can be assessed using a unified dimensionless plot. Effects of the intersection angle between the pipe bursting centerline and adjacent pipeline are explored. The pipe responses are shown to be underestimated or unconservative when only the perpendicular case is considered in the analysis.

Numerical modeling of tunneling effect on buried pipelines

2011 ◽  
Vol 48 (7) ◽  
pp. 1125-1137 ◽  
Author(s):  
Yu Wang ◽  
Jiangwei Shi ◽  
Charles W.W. Ng
Keyword(s):  
Urban Areas ◽  
Ground Movement ◽  
Tunneling Effect ◽  
Burial Depth ◽  
Test Results ◽  
Soil Stiffness ◽  
Bending Strain ◽  
Versus Ratio ◽  
Parametric Studies ◽  
Soil Responses

The underground space in urban areas is frequently congested with utilities, including pipelines and conduits, that are affected by underground construction, e.g., tunneling. This paper carries out finite element (FE) analyses to investigate the effects of tunneling-induced ground movement on pipelines, with special attention to the different soil responses to uplift and downward pipe–soil relative movements. A series of numerical parametric studies with 900 FE simulation runs in total is performed to encompass various combinations of ground settlement profiles, pipe dimensions, material properties, pipe burial depth, and soil properties that are typical for utility pipelines and tunnel construction in urban areas. The results are summarized in a dimensionless plot of relative pipe–soil stiffness versus ratio of maximum pipe curvature to maximum ground curvature, which can be used to directly estimate the maximum pipe bending strain and (or) to directly assess the tunneling-induced risk to pipelines. The FE results and dimensionless plot are validated against field and centrifuge test results reported in the literature. Effect of pipeline orientation with respect to the tunnel centerline is explored. It might be unconservative if design analysis only considers the case that the pipeline is perpendicular to the tunnel centerline.

A Digital Terrain Modeling Method in Urban Areas by the ICESat-2 (Generating precise terrain surface profiles from photon-counting technology)

2021 ◽  
Vol 87 (4) ◽  
pp. 237-248
Author(s):  
Nahed Osama ◽  
Bisheng Yang ◽  
Yue Ma ◽  
Mohamed Freeshah
Keyword(s):  
Urban Areas ◽  
Spatial Clustering ◽  
Photon Counting ◽  
Ground Surface ◽  
Ground Truth ◽  
Surface Model ◽  
Laser Altimeter ◽  
Ground Truth Data ◽  
Urban Scenes ◽  
Terrain Surface

The ICE, Cloud and land Elevation Satellite-2 (ICES at-2) can provide new measurements of the Earth's elevations through photon-counting technology. Most research has focused on extracting the ground and the canopy photons in vegetated areas. Yet the extraction of the ground photons from urban areas, where the vegetation is mixed with artificial constructions, has not been fully investigated. This article proposes a new method to estimate the ground surface elevations in urban areas. The ICES at-2 signal photons were detected by the improved Density-Based Spatial Clustering of Applications with Noise algorithm and the Advanced Topographic Laser Altimeter System algorithm. The Advanced Land Observing Satellite-1 PALSAR –derived digital surface model has been utilized to separate the terrain surface from the ICES at-2 data. A set of ground-truth data was used to evaluate the accuracy of these two methods, and the achieved accuracy was up to 2.7 cm, which makes our method effective and accurate in determining the ground elevation in urban scenes.

scholarly journals Adopting Numerical Models for Prediction of Ground Movements Induced by Deep Excavation

2020 ◽  
Vol 8 (6) ◽  
pp. 976-989
Keyword(s):  
Numerical Models ◽  
Ground Surface ◽  
Sensitivity Study ◽  
Design Criterion ◽  
Deep Excavation ◽  
Soil Behavior ◽  
Analysis And Design ◽  
Ground Movements ◽  
Codes Of Practice ◽  
Adjacent Structures

Control of ground surface settlement induced by deep excavation is of major concern in order to attain safety of adjacent structures and utilities against excessive or differential settlements. Accurate prediction of ground surface movements is an important design criterion in the analysis and design of excavation supporting systems. Many codes of practice are based on a design criterion that satisfies a factor of safety preventing collapse of the system and its surrounding soil. In this research, finite element modeling is adopted to numerically simulate the performance of deep excavation systems and the associated ground movements. The soil behavior was simulated using two types of models; the Mohr-Coulomb model (MC) and the Hardening Soil Model (HS). Field data from monitoring a real deep excavation case history of a retaining system was considered to check the validity of the proposed numerical modeling. A simpler equivalent section replacing the multi-layered soil profile was verified. Then, a sensitivity study has been conducted to study the influence of major parameters that affect ground movements induced by deep excavation. The results of the parametric study were accomplished to construct design charts and drive empirical equations by implementing a design parameter, called the "Stiffness Ratio (R)”, that represents the supporting system stiffness. From these suggested charts and equations, the percentage of maximum vertical ground movements to wall height can be estimated.

scholarly journals An Equal-Strain Analytical Solution for the Radial Consolidation of Unsaturated Soils by Vertical Drains considering Drain Resistance

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Feng Zhou ◽  
Zheng Chen ◽  
Xudong Wang
Keyword(s):  
Analytical Solution ◽  
Unsaturated Soils ◽  
Ground Surface ◽  
Matrix Analysis ◽  
Governing Equations ◽  
Vertical Drains ◽  
Ground Surface Settlement ◽  
Parametric Studies ◽  
Strain Model ◽  
Good Agreement

Developing an analytical solution for the consolidation of unsaturated soils remains a challenging task due to the complexity of coupled governing equations for air and water phases. This paper presents an equal-strain model for the radial consolidation of unsaturated soils by vertical drains, and the effect of drain resistance is also considered. Simplified governing equations are established, and an analytical solution to calculate the excess pore-air and pore-water pressures is derived by using the methods of matrix analysis and eigenfunction expansion. The average degrees of consolidation for air and water phases and the ground surface settlement are also given. The solutions of the equal-strain model are verified by comparing the proposed free-strain model with the equal-strain model, and reasonably good agreement is obtained. Moreover, parametric studies regarding the drain resistance effect are graphically presented.

scholarly journals Innovative Seismic Microzonation Maps of Urban Areas for the Management of Building Heritage: A Catania Case Study

Geosciences ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 480
Author(s):  
Glenda Abate ◽  
Simone Bramante ◽  
Maria Rossella Massimino
Keyword(s):  
Urban Areas ◽  
Large Scale ◽  
Free Field ◽  
Ground Surface ◽  
Seismic Microzonation ◽  
Field Conditions ◽  
Seismic Retrofitting ◽  
Geotechnical Characteristics ◽  
Fixed Base ◽  
Scale Estimate

Several urban areas in the Mediterranean have already been subjected to seismic microzonation studies aimed at determining the acceleration expected on the ground surface, therefore mitigating the associated seismic risks. These studies have been generally related to free-field conditions. The present paper shows innovative seismic microzonation maps based on a large-scale estimate of soil-structure interaction (SSI) effects on design accelerations for some areas characterized by a high seismic risk in Catania, Italy. The proposed procedure combined: (1) geotechnical characteristics; (2) building features; and (3) 1-D seismic response analyses in free-field conditions. The seismic hazard and site effects were evaluated using artificial inputs and inputs recorded recently in Catania. Structural fundamental periods and related spectral accelerations, considering both the fixed-base building configuration and flexible-base configuration, were mapped in the Google My Maps environment. These results showed that SSI often had a beneficial effect, but sometimes it had detrimental effects, especially for some masonry buildings. These maps provided important information for planning the seismic retrofitting of investigated buildings, which were based on more detailed analyses of SSI and the developed maps requiring them.

scholarly journals 3D MODELLING OF TUNNEL EXCAVATION USING PRESSURIZED TUNNEL BORING MACHINE IN OVERCONSOLIDATED SOILS

2013 ◽  
Vol 35 (2) ◽  
pp. 3-17 ◽  
Author(s):  
Rafik Demagh ◽  
Fabrice Emeriault
Keyword(s):  
Numerical Simulation ◽  
Urban Areas ◽  
Three Dimensional ◽  
Ground Surface ◽  
Tunnel Boring Machine ◽  
Confining Pressure ◽  
Soil Mass ◽  
Shield Tunnel ◽  
Tunnel Boring ◽  
Boring Machines

Abstract The construction of shallow tunnels in urban areas requires a prior assessment of their effects on the existing structures. In the case of shield tunnel boring machines (TBM), the various construction stages carried out constitute a highly three-dimensional problem of soil/structure interaction and are not easy to represent in a complete numerical simulation. Consequently, the tunnelling- induced soil movements are quite difficult to evaluate. A 3D simulation procedure, using a finite differences code, namely FLAC3D, taking into account, in an explicit manner, the main sources of movements in the soil mass is proposed in this paper. It is illustrated by the particular case of Toulouse Subway Line B for which experimental data are available and where the soil is saturated and highly overconsolidated. A comparison made between the numerical simulation results and the insitu measurements shows that the 3D procedure of simulation proposed is relevant, in particular regarding the adopted representation of the different operations performed by the tunnel boring machine (excavation, confining pressure, shield advancement, installation of the tunnel lining, grouting of the annular void, etc). Furthermore, a parametric study enabled a better understanding of the singular behaviour origin observed on the ground surface and within the solid soil mass, till now not mentioned in the literature.

Ground Displacements from a Pipe-Bursting Experiment in Well-Graded Sand and Gravel

2009 ◽  
Vol 135 (11) ◽  
pp. 1713-1721 ◽  
Author(s):  
J. A. Cholewa ◽  
R. W. I. Brachman ◽  
I. D. Moore ◽  
W. A. Take
Keyword(s):  
Pipe Bursting ◽  
Sand And Gravel ◽  
Ground Displacements

scholarly journals Stability assessment of roadbed affected by ground subsidence adjacent to urban railways

2017 ◽  
Author(s):  
Ki-Young Eum ◽  
Young-Kon Park ◽  
Sang-Soo Jeon
Keyword(s):  
South Korea ◽  
Urban Areas ◽  
Three Dimensional ◽  
Ground Surface ◽  
Ground Subsidence ◽  
Risk Level ◽  
Train Derailment ◽  
Groundwater Levels ◽  
Modeling Software ◽  
Ground Conditions

Abstract. In recent years, leakages in aged pipelines for water and sewage in urban areas have frequently induced ground loss resulting in cavities. One third of the pipelines buried in Seoul city in South Korea are more than fifty years old. Train loadings and change in groundwater levels in the undiscerned development of urban areas induce roadbed settlements. Train derailment may occur as the roadbed exceeds the allowable settlements associated with location and size of the cavity adjacent to the roadbed. In this study, FLAC3D, which is a three-dimensional finite-difference numerical modeling software, is used to do stability and risk level assessment for the roadbed in adjacent to urban railways with respect to various groundwater levels and the geometric characteristics of cavities. Numerical results show that the roadbed settlements in simulated ground conditions in South Korea, that satisfy the allowable values for a cavity of diameter of 10 m exists adjacent to the roadbed. The distance between the center of the roadbed and the center of the cavity should be greater than 25 m and the groundwater level should be greater than 22 m below the ground surface.

scholarly journals Construction Cost Analysis of Retaining Walls

2020 ◽  
Vol 9 (4) ◽  
pp. 1909-1914
Keyword(s):  
Urban Areas ◽  
Ground Surface ◽  
Retaining Walls ◽  
Soil Mass ◽  
Strength Properties ◽  
Wall Material ◽  
Sharp Change ◽  
Finite Element Software ◽  
Special Cases ◽  
The Cost

Retaining walls are relatively rigid walls used to support the ground laterally so that it can be held at different levels on both sides [1]. Retaining walls are considered all technical works, which allow the implementation of a sharp change in the level of the earth's surface, in such a way that the ground-construction system presents limited displacement or is marginally restrained. Support structures are mainly used in cases of disruption of soil continuity resulting from an excavation, below the natural surface of the ground, such as when building roads in a difficult geographical terrain with steep slopes. It is also common for them to be used in the construction of basements in urban areas, when there are other buildings or roads around the perimeter. In special cases, functional reasons impose the local elevation of the ground surface with grounding in the area around the construction, such as on bridge piers or in port projects, so it becomes necessary to support the soil mass. Finally, the construction of retaining walls becomes necessary to stabilize and protect natural slopes that present kinematic instability. The purpose of the present work is to compare the cost of constructing three retaining walls (gravity, cantilever, braced) subject to identical ground pressures. The retaining walls were designed using the same finite element software (GEO5), taking into account common parameters for the soil stress, the strength properties of the soil mass, the wall material as well as the diameter of the reinforcing steel bars, so that the results can be absolutely comparable. The market research that followed produced interesting conclusions on the comparison of the cost estimates for the three retaining walls

scholarly journals An Investigation of Effects and Safety of Pipelines due to Twin Tunneling

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Shao Yu ◽  
Riyan Lan ◽  
Junhui Luo ◽  
Zhibo Duan ◽  
Shaokun Ma
Keyword(s):  
Soil Parameters ◽  
Centrifuge Model Test ◽  
Burial Depth ◽  
Buried Pipelines ◽  
Soil Stiffness ◽  
Maximum Settlement ◽  
Dimensionless Analysis ◽  
Bending Strain ◽  
Calculation Results ◽  
Subway Tunnels

To efficiently and accurately predict the effects of twin tunneling on adjacent buried pipelines, the effects of upward and downward relative pipeline-soil interactions were considered. A series of numerical parametric studies encompassing 8640 conditions were performed to investigate the responses of a pipeline to twin tunneling. Based on the dimensionless analysis and normalized calculation results, the concept of equivalent relative pipeline-soil stiffness was proposed. Additionally, expressions for the relative pipeline-soil stiffness and relative pipeline curvature and for the relative pipeline-soil stiffness and relative pipeline settlement were established, along with the related calculation plots. Relying on a comparison of prediction results, centrifuge model test results, and field measured results, the accuracy and reliability of the obtained expressions for predicting the bending strain and settlement of adjacent buried pipelines caused by twin tunneling were validated. Based on the calculation method, the maximum bending strain and maximum settlement of pipelines can be calculated precisely when the pipeline parameters, burial depth, soil parameters, and curve parameters of ground settlement due to tunneling are provided. The proposed expressions can be used not only to predict the maximum bending strain and maximum settlement of pipelines caused by single and twin tunneling but also to evaluate the effects of single and twin tunneling on the safety of existing buried pipelines. The relevant conclusions of this article can also provide a theoretical basis for the normal service of buried pipelines adjacent to subway tunnels.

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