Seasonal Ground Movements Research Articles

Influence of Weather, Soil Variability, and Vegetation on Seasonal Ground Movement: A Field Study

Influence of Weather, Soil Variability, and Vegetation on Seasonal Ground Movement: A Field Study

Seasonal Subsidence and Heave Recorded by Borehole Extensometers in Houston

Seasonal ground movements, particularly subsidence and heave, present a great challenge for the design of roadways, parking lots, underground utility lines, and buried culverts. The US Geological Survey has been operating 13 deep borehole extensometers in Houston, Texas, for land subsidence monitoring since the 1970s and the early 1980s. The half-century extensometer datasets provide direct and continuous measurements of seasonal ground movements in the vertical direction. The Houston global positioning system (GPS) network (HoustonNet) provides independent measures for the timely evaluation of extensometer data. According to this study, shallow expansive soils can induce up to 4 cm (peak-to-trough) seasonal subsidence and heave, and deep sediments can further produce up to 2 cm seasonal subsidence and heave. The latter is primarily caused by the seasonal fluctuations of hydraulic heads in the lower Chicot and upper-Evangeline aquifers, varying considerably over time and space. The results from this study are important for determining potential vertical movement (PVM) for the design of pavements and shallow foundations and for the optimization of groundwater management in the Houston region.

Sentinel-1 InSAR and GPS-Integrated Long-Term and Seasonal Subsidence Monitoring in Houston, Texas, USA

For approximately 100 years, the Houston region has been adversely impacted by land subsidence associated with excessive groundwater withdrawals. The rapidly growing population in the Houston region means the ongoing subsidence must be vigilantly monitored. Interferometric synthetic aperture radar (InSAR) has become a powerful tool for remotely mapping land-surface deformation over time and space. However, the humid weather and the heavy vegetation have significantly degraded the performance of InSAR techniques in the Houston region. This study introduced an approach integrating GPS and Sentinel-1 InSAR datasets for mapping long-term (2015–2019) and short-term (inter-annual, seasonal) subsidence within the greater Houston region. The root-mean-square (RMS) of the detrended InSAR-displacement time series is able to achieve a subcentimeter level, and the uncertainty (95% confidence interval) of the InSAR-derived subsidence rates is able to achieve a couple of millimeters per year for 5-year or longer datasets. The InSAR mapping results suggest the occurrence of moderate ongoing subsidence (~1 cm/year) in nothwestern Austin County, northern Waller County, western Liberty County, and the city of Mont Belvieu in Champers County. Subsidence in these areas was not recognized in previous GPS-based investigations. The InSAR mapping results also suggest that previous GPS-based investigations overestimated the ongoing subsidence in southwestern Montgomery County, but underestimated the ongoing subsidence in the northeastern portion of the county. We also compared the InSAR- and GPS-derived seasonal ground movements (subsidence and heave). The amplitudes of the seasonal signals from both datasets are comparable, below 4 mm within non-subsiding areas and over 6 mm in subsiding (>1 cm/year) areas. This study indicates that groundwater-level changes in the Evangeline aquifer are the primary reason for ongoing long-term and seasonal subsidence in the Houston region. The former is dominated by inelastic deformation, and the latter is dominated by elastic deformation. Both could cause infrastructure damage. This study demonstrated the potential of employing the GPS- and InSAR-integrated method (GInSAR) for near-real-time subsidence monitoring in the greater Houston region. The near-real-time monitoring would also provide timely information for understanding the dynamic of groundwater storage and improving both long-term and short-term groundwater resource management.

Thornthwaite Moisture Index and Climate Zones in the Northern Territory

The Thornthwaite Moisture Index (TMI) is an established climate parameter for geotechnical engineers to categorise a site and enable estimation of seasonal ground movements associated with soil moisture changes. TMI assessment and mapping for the Northern Territory are presented, using the TMI calculation method commonly used for similar recent studies elsewhere in Australia. The assessment included the analysis of 17 sites within the Northern Territory and one site in Queensland which has enabled development of Climate Zone classifications. Climate data was obtained from the Australian Bureau of Meteorology to calculate the TMI on a ‘year by year’ basis over a target period of 29 years (1990 to 2019). Related work in Queensland (Fox 2002) and Western Australia (Hu et al, 2016) has guided the development of the Northern Territory Climate Zone Map. Further work is required to characterise the soil moisture behaviour in arid zones. A general lack of guidance in AS2870 (2011) for arid areas, including much of the Northern Territory, could be addressed with further research and development.

Seasonal Ground Movement Due to Swelling/Shrinkage of Nicosia Marl

This research investigates the seasonal ground heave/settlement of an area covered by an expansive soil of Cyprus called Nicosia marl, highlighting the degree of influence of the main causal factors. For this purpose, existing geotechnical data from the archives of the Cyprus Geological Survey were first collected and processed to compile maps of the key geotechnical parameters in the study area. In order to estimate the ground movements in the area, Earth Observation (EO) techniques for the period between 16 November 2002–30 December 2006 were processed. The correlation of these movements with the existing geotechnical data indicates that there is a statistically significant correlation between plasticity index and the ground movements. Multivariate linear regression analysis using Lasso revealed that the plasticity index ranks first in importance among the examined variables.

Ice loss in the Northeastern Tibetan Plateau permafrost as seen by 16 yr of ESA SAR missions

InSAR time series of surface deformation from 16 yr of Envisat (2003-2011) and Sentinel-1 (2014-2019) ESA satellite radar measurements have been constructed to characterise spatial and temporal dynamics of ground deformation over an 80,000km2 area in the permafrost of the northeastern Tibetan Plateau. The regional deformation maps encompass various types of periglacial landforms and show that seasonal thaw effects are controlled by the sediment type and local topography. High seasonal ground movements are concentrated on shallow slopes and poor-drainage areas in unconsolidated, frost-susceptible and fine-grained sediments within glacier outwash plains, braided stream plains, alluvial deposits or floodplains. Fast subsidence due to thaw settlement takes place during June/July while frost heave is intense during December/January when two-sided freezing of pore water under pressure causes prolonged ice segregation near the permafrost table. The analysis reveals pervasive subsidence of the ground of up to ∼2 cm/yr, and increasing by a factor of 2 to 5 from 2003 to today, in high-relief and well-drained areas. The findings suggest that seasonal thaw increasingly affects ice-rich layers at the permafrost table, as well as high-rates of widespread mass movements of non-consolidated sediments, the latter amplified by an increase of effects from frost heave/thaw settlement.

Limitations of Persistent Scatterer Interferometry to measure small seasonal ground movements in an urban environment

London Clay, which underlies the majority of Greater London, has a high shrink–swell potential that can result in damage to foundations and surface infrastructure due to seasonal expansion and contraction of the clay. Currently, surface movement as a result of shrink–swell is not monitored in London, meaning that the magnitude and cyclicity of these movements is poorly understood. Persistent Scatterer Interferometric (PSI) Synthetic Aperture Radar data provide high-precision line-of-sight displacement measurements at a high point density across urban areas, offering the possibility of routine shrink–swell monitoring across whole cities. To test this, PSI data derived from TerraSAR-X (TSX) observations for the period from May 2011 to April 2017 were analysed for shrink–swell patterns across three areas of London in Hammersmith, Muswell Hill and Islington. A consistent cyclicity and amplitude was detected at all sites and the number of cycles is comparable with those identified in rainfall data. The amplitude of these cycles is smaller than anticipated, most probably because of the resisting effect of roads and pavements. The Cranfield University Leakage Assessment from Corrosivity and Shrinkage (LEACS) database was used to subdivide the PSI data and the average velocity and amplitude of each class statistically tested for significant differences between classes. The results show that it is not possible to statistically isolate possible soil shrink–swell movement in TSX PSI data in London. Thematic collection: This article is part of the Measurement and monitoring collection available at: https://www.lyellcollection.org/cc/measurement-and-monitoring

The influence of tree root water uptake on the long term hydrology of a clay fill railway embankment

This paper uses a numerical model to investigate the influence of tree root water uptake and tree removal on pore water pressures and the vertical movement of a clay fill railway embankment. Simulated results of soil wetting and drying are compared with field measurements from an instrumented railway embankment before and after tree removal. A parametric study compares the influence of vegetation on the seasonal movement of the embankment slope. The simulations and field measurements show that while trees cause significant seasonal variations in pore water pressure and water content near the soil surface, they can maintain persistent soil suctions at depth within the tree rooting zone. Demonstration of this result using a numerical model requires a root water uptake function that separates spatially the processes of water infiltration, evaporation and transpiration. When all of the trees are removed, the persistent soil suctions established by the trees are lost as water infiltrates from the soil surface. Leaving the trees in place over the bottom third of the slope can maintain persistent suctions at the slope toe, while potentially also reducing seasonal ground movements at the crest that may adversely affect railway track geometry.

Effect of an oak tree on seasonal ground movements in the Lower Lias Clay, Bristol, UK

Changes in ground elevation were monitored between 1990 and 1997 at depths of 0.4, 0.8, 1.2 and 1.6 m and distances of 1, 2.5, 5, 10, 15, 20, 25 and 50 m from a mature oak tree on the Lias Clay of Lower Jurassic age. Whilst movement was evident at all monitoring points, it was most pronounced within 5 m of the tree where in 1995 a maximum seasonal difference of 63 mm was recorded at 0.4 m depth, compared with only 14 mm at the same depth but 10 m from the tree. The influence of the tree on the geotechnical properties of the Liassic clays is reported.

A comparison of field measured and numerically simulated seasonal ground movement in unsaturated clay : H. R. Thomas & Z. Zhou, International Journal for Numerical & Analytical Methods in Geomechanics, 19(4), 1995, pp 249–265

A comparison of field measured and numerically simulated seasonal ground movement in unsaturated clay : H. R. Thomas & Z. Zhou, International Journal for Numerical & Analytical Methods in Geomechanics, 19(4), 1995, pp 249–265

A comparison of field measured and numerically simulated seasonal ground movement in unsaturated clay

AbstractThis paper presents the results of a numerical simulation of field measured seasonal ground movement. The constitutive model employed was proposed as a practical method of modelling the complex stress/strain behaviour of unsaturated soil. Its use within a consolidation‐type analysis is explored here, as a means of assessing its suitability for practical application. Comparisons are given of numerical results and field measured behaviour over a 9 month period of time. Overall good correlation is achieved, covering a series of drying and wetting cycles. Confidence can thus be ascribed to the performance of the constitutive model.

Seasonal ground movement in unsaturated clay: an examination of field behaviour : H.R. Thomas & S. W. Rees, Geotechnique, 44(2), 1994, pp pp 353–358

Seasonal ground movement in unsaturated clay: an examination of field behaviour : H.R. Thomas & S. W. Rees, Geotechnique, 44(2), 1994, pp pp 353–358

Seasonal ground movement in unsaturated clay: an examination of field behaviour

Keywords: case history ; deformation ; field instrumentation, numerical modelling and analysis ; partial saturation ... Show All

Simulating seasonal ground movement in unsaturated clay : S. W. Rees & H. R. Thomas, Journal of Geotechnical Engineering - ASCE, 119(7), 1993, pp 1127–1143

Simulating seasonal ground movement in unsaturated clay : S. W. Rees & H. R. Thomas, Journal of Geotechnical Engineering - ASCE, 119(7), 1993, pp 1127–1143

Simulating seasonal ground movement in unsaturated clay : Rees, S W; Thomas, H R J Geotech Engng Div ASCEV119, N7, July 1993, P1127–1143

Simulating seasonal ground movement in unsaturated clay : Rees, S W; Thomas, H R J Geotech Engng Div ASCEV119, N7, July 1993, P1127–1143

Simulating Seasonal Ground Movement in Unsaturated Clay

The results of a theoretical, experimental, and numerical investigation into the volume‐change behavior of an unsaturated clay are described. The theoretical approach adopted is presented and its implementation detailed. The work is shown to be analogous to Terzaghi's classical theory of one‐dimensional consolidation for saturated soils. An experimental procedure is proposed for the determination of appropriate one‐dimensional soil properties. The procedure is used to determine the variation of volumetric strain and volumetric moisture content with respect to capillary potential for the Kimmeridge clay under consideration. The experimental results achieved are used to obtain deformation moduli that are applied in a simulation of seasonal ground movement. In particular, ground movements corresponding to previously determined moisture‐content variations over the 1983 period are predicted. The results of the numerical simulation are assessed qualitatively and quantitatively by comparison with field‐measured ...

Numerical modelling of vertical ground movements in expansive, soils

A numerical model was developed to relate matric suction changes and vertical ground movements. The research considers one-dimensional vertical ground movements under open-vegetated fields subject to changing climatic conditions. A percentage of the Thornthwaite potential evapotranspiration model proved to be adequate to characterize the surface flux boundary condition. The infiltration and exfiltration processes were modelled separately for the field conditions. During infiltration, shrinkage cracks and the macrostructure of the soils dominate behavior. During this process, bulk permeabilities in the order of 10−6–10−8 m/s were required to simulate measured ground movements. Exfiltration processes are dominated by flow in the vapour phase as drying occurs in the soil. Bulk permeabilities in the order of 10−9–10−11 m/s were required to simulate the measured ground movement. The simulations of ground movements would also indicate that thermally induced suctions (i.e., winter freezing conditions) could account for a significant portion of the seasonal vertical ground movements. The numerical model can also be used to predict seasonal ground movements beneath light engineered structures. Further research, however, is required to better understand how to establish the surface flux boundary condition. As well, there is need for more case histories to enlarge the database of unsaturated soil parameters. Key words: vertical ground movement, matric suction, modelling, evapotranspiration, field permeabilities.