Building Subsidence Research Articles

A Comparison of Precise Leveling and Persistent Scatterer SAR Interferometry for Building Subsidence Rate Measurement

It is well known that the most accurate method to detect changes of height is the geodetic precise leveling method. Due to the high demand work and time needed for precise leveling alternative methods are studied to obtain high quality height information. Differential SAR interferometry techniques such as the Persistent Scatterer Interferometry (PSI) method are studied to detect millimeter level deformations in urban areas. Additionally, SAR analysis will provide spatially extensive information on subsidence. On the other hand, PSI subsidence rates have not yet been comprehensively compared to the precise leveling measurements of the subsidence of individual buildings. Typically subsidence rates are interpolated to a continuous spatial surface, but in this study, spatially discontinuous subsidence was measured for a set of individual buildings. Therefore, we conducted three precise leveling campaigns and measured in total 82 geodetic-grade bolts, which were tightly attached to the building foundations. Moreover, we used additional leveling data (obtained from the local authorities), which contained long time series of leveling data for individual buildings. In the present study, ERS and ENVISAT satellite SAR data were processed using a PSI algorithm and the results were compared to leveling data of individual buildings.

The Development of a Realtime Remote Monitoring System for the Subsidence of Building

A system, which is real-time, remote, automatic for monitoring the subsidence of building, is introduced. Hydrostatic leveling, displacement sense by electromagnetism, computer technology are integrated into the system. The system can realize real-time, continuous acquisition and management of the measured data, and when the quantity and speed of the subsidence exceed the certain warning value,the system can realize automatic early-warning. Compared with geometrical leveling, the system has advantages of high accuracy, real time, continuous, unattended, remote, wireless for monitoring and early-warning.

Dynamic prediction of building subsidence deformation with data-based mechanistic self-memory model

This paper describes a building subsidence deformation prediction model with the self-memorization principle. According to the non-linear specificity and monotonic growth characteristics of the time series of building subsidence deformation, a data-based mechanistic self-memory model considering randomness and dynamic features of building subsidence deformation is established based on the dynamic data retrieved method and the self-memorization equation. This model first deduces the differential equation of the building subsidence deformation system using the dynamic retrieved method, which treats the monitored time series data as particular solutions of the nonlinear dynamic system. Then, the differential equation is evolved into a difference-integral equation by the self-memory function to establish the self-memory model of dynamic system for predicting nonlinear building subsidence deformation. As the memory coefficients of the proposed model are calculated with historical data, which contain useful information for the prediction and overcome the shortcomings of the average prediction, the model can predict extreme values of a system and provide higher fitting precision and prediction accuracy than deterministic or random statistical prediction methods. The model was applied to subsidence deformation prediction of a building in Xi’an. It was shown that the model is valid and feasible in predicting building subsidence deformation with good accuracy.

THE RELATIONSHIP BETWEEN TREES, DISTANCE TO BUILDINGS AND SUBSIDENCE EVENTS ON SHRINKABLE CLAY SOIL

An investigation of the incidents of trees causing building subsidence was undertaken as a re-investigation of the data reported in the Kew Root Survey undertaken by CUTLER and RICHARDSON in 1981, and expanded in 1989. This investigation was undertaken 26 years after the Kew Root Survey was first reported. The databases of the major loss assessor (Cunningham Lindsey UK Ltd); the site investigation company (The CET Group Ltd); the tree root identification Labs (Tree Root Investigations Ltd) and the major arboricultural consultancy company involved in subsidence (OCA UK Ltd) were interrogated. The study reveals that although there are some minor differences between the data reported in the Kew Root Survey of 1981 and the data in the present study, the findings of the Kew Root Survey are vindicated. A discussion about tree rooting strategies is included because of the historic reliance that Arboriculturists and others place on the straight line distances between trees and building damage.

A Real-Time Remote Automatic System for Monitoring the Subsidence of Building

A system, which is real-time, remote, automatic for monitoring the subsidence of building, is introduced. Hydrostatic leveling, displacement sensing by electromagnetism, GPRS wireless communication and computer technology are integrated into the system. The system has the following functions: real-time, continuous acquisition and management of the monitored data; automatic computation and analysis of the subsidence; remote, wireless release of information and early-warning. Applied successfully to monitor the subsidence of the main building of Tianjin West Railway Station in its integral moving, the system has taken the key directive effect in adjusting the schedule and the methods of construction timely.

Research on the effect of underground tunnelling on the settlement of the building and the ground surfaces

The construction of underground tunnel plays a more and more important role on the development of big cities. One of the most important problems caused by the construction of tunnel is that underground excavation will cause large settlements of ground buildings. And it heavily affects the safety of the building. The depth of underground tunnel and the horizontal distance between the tunnel and the building are two important factors which have great influence on the settlements of ground buildings. During the designing of tunnels these two factors must be taken into account. It is necessary to find out the regulations between the settlements of buildings and those two factors. On the other hand, the loess plateau in the west of China has a vast territory, integrated strata and large depth, which is rare in the world. Currently in big cities located in the loess areas, such as Xi'an, underground tunnel is preferred to be adopted to solve the traffic problem. So it is of great importance for the construction of underground project to research the relationship between the building subsidence and the excavation of underground cavity or the construction of underground tunnel in western China. This paper will aim to find out the quantity rules that how the underground tunnels affect the settlements of ground buildings in the loess areas. According to the mechanical characteristic of loess, the Duncan-Chang non-linear elastic constitutive model will be adopted; through the simulation in term of the FEA program- GeoFBA, the regulation that how the depth of underground tunnel and the horizontal distance between the tunnel and the buildings influence the settlements of ground buildings, will be obtained. And this result can be used as theoretic reference to the construction of the underground engineering in loess areas. (A) This paper was presented at Safety in the underground space - Proceedings of the ITA-AITES 2006 World Tunnel Congress and the 32nd ITA General Assembly, Seoul, Korea, 22-27 April 2006. For the covering abstract see ITRD E129148. Reprinted with permission from Elsevier.

Tree-related subsidence: Pruning is not the answer

Building subsidence is a major problem in the UK and has been for many years. Most subsidence problems are tree-related and the cost to the insurance sector runs into hundreds of millions of pounds a year. Subsidence damage ranges from minor cracking to significant structural damage and trees are sometimes viewed negatively because of their role in subsidence damage. There are over 150 million urban trees in Britain and a significant majority of these are legally protected by tree preservation orders or by virtue of the fact that they are in conservation areas. There has been simplistic and erroneous advice available for a number of years that is based on a false premise that pruning offers a means to control tree water use sufficiently to provide a remedy for tree-related subsidence. This paper presents a factual account of the biology involved in how trees use water, together with the results of recent research into the subject, that cogently dispose of the false premise that has dominated the subject since the 1970s. A simple ‘model tree’ is presented in the context of clay soils, climate, building guidelines, the housing stock and management options. Recent case law in this area is placed in the context of the legal framework surrounding the issue and the effect of tree removals on the nation's urban tree population is discussed.

Evaporite dissolution subsidence in the historical City of Calatayud, Spain: Damage appraisal and prevention

Calatayud in NE Spain is an historically important city built on recent alluvial deposits underlain by gypsum and other soluble rocks. Since its foundation by the Muslims in 716 A.D., the city development has been strongly influenced by geohazards including flooding, subsidence and slope movements. Most of the flooding problems have been mitigated by diversion of the local drainage. However, dissolution of the evaporite bedrock in the urban areas continually causes subsidence and triggers rock-falls from the gypsum cliffs overlooking the city. Subsidence is also caused by the hydrocollapse of gypsiferous silt in the alluvial fan deposits. Building damage in the city was surveyed using a classification scheme developed originally to record damage in British coal mining areas. The Calatayud damage survey shows that the worst building subsidence is concentrated along the line of a buried channel that runs underneath the gypsiferous silt alluvial fan. Natural subsurface drainage causes the dissolution and subsidence, which is aggravated by leakage from water and sewage pipes. Some building damage has been exacerbated during reconstruction by incomplete piling leaving buildings partially unsupported. Mitigation measures include the control of water leakage by the installation of flexible service pipes. Careful construction techniques are needed for both conservation and new developments, especially when piled and minipiled foundations are used. Geomorphological mapping is cost-effective in helping to locate and avoid the zones of subsidence for future development.

ポートアイランドの液状化被害への測量学的考察

Port-island is offshore artificial island of 436 hectare area which has both functions of a harbor and a city. The new city planning which surrounded residential area in a public institution has been done. Residential area is constituted in high altitude condominium and many community institutions of citizen hospital, international convention facility, international exhibition building is built as surrounding a condominium group.Kobe city received the big damage by South Hyogo earthquake that occurred at 5: 46 am on January 17, 1995. The people who can't get information of outside by the damage of life line and liquefaction damage spent an anxious few days. Our country is narrow, we need to continue construction of artificial island as utilization the space. So it is important to compare an amount of subsidence of building and ground of before and after an earthquake disaster.This paper describes liquefaction damage of Port-island using observation result of leveling and satellite image