Foundation For Investigation Research Articles

Large-diameter piles in chalk – part 1, ground investigation

Deep bored piled foundations were planned to support a new 279 m tall tower in east London. The piles were founded in chalk, and therefore detailed stratigraphical logging of the chalk strata was carried out using known marker bands such as flints bands and marl seams. This helped to develop a ground model, including the separation of the various chalk formations into their respective beds. Other investigation methods were employed to assist in developing the chalk stratigraphy, including downhole geophysical techniques, fluid temperature, fluid flow, resistivity, density, caliper and natural gamma. Other downhole tools, such as downhole optical imaging, were also used. Critical to the design of the pile was understanding the behaviour of the bentonite support fluid when used in chalk. Owing to concerns regarding the possible interaction of the bentonite with the chalk, bespoke laboratory tests were carried out on core samples using two commonly used bentonite types. The tests were carried out at two bentonite concentrations with chalk samples from three depths. Control samples were also tested without chalk. This paper presents the detailed investigation of the chalk and its interaction with the bentonite carried out prior to the commencement of the pile design.

Stretching AEM near-surface resolution limits related to low- and very high resistivity contrasts

Data from AEM surveys carried out in Norway, to support ground investigations for infrastructure projects, were used in this study. In large infrastructure projects, knowledge of sediment thickness is vital, along with information about sediment type as possible occurrence of highly sensitive clay. The acquisition systems, calibration and data processing are continuously improved to increase the sensitivity of the AEM systems. In an area with conductive shales over resistive bedrock, the recently introduced system response method was tested. It is applied in the inversion of SkyTEM data and makes it possible to utilize the very earliest time gates, providing information about the shallower layers. The models showed to give more pronounced structures in the near-surface, reflecting true structures observed in resistivity borehole measurements. The same outcome was observed when conducting synthetic modelling. In another setting AEM measurements were carried out along a planned road project to provide information about the extent of very conductive, possible alum shale. A volume estimate of excavated masses was sought, as alum shale poses an environmental and health risk due to the decomposition to sulfuric acid by weathering and high uranium content giving radon gas. Preliminary AEM models had a tendency to overestimate the thickness of the very resistive overburden. Experimenting with and optimizing the inversion settings resulted in models better fitting a priori information from the survey area. Limited low moment data were available due to a noisy environment. This affected the reliability of the models, illustrated by modelling and resulting real data models.

Resolving Changes to Freshwater Lens Systems in a “Sea of Salinity” using Multi-date Airborne EM

Saline aquifers in the Murray River or SE Australia are traversed by freshwater rivers, with adjoining riparian and floodplain regions containing freshwater lenses. Bore data and more recent Airborne electromagnetic (AEM) surveys have determined that these lenses are spatially extensive, but have widely varying geometries. The maintenance of these lens systems is important as they support ecologically significant riparian vegetation communities such as Red Gum and Black Box. A more complete understanding of their hydrogeology is required to ascertain how they develop and degrade. Limited ground investigations including 14C geochemistry have determined that the lens systems contain recent water, indicating that they are dynamic systems with their development defined by the relative rates of recharge from the river and mixing with groundwater. Changes in groundwater gradients and depth, floodplain extent, and topography are believed to control their initial location. The same controls also govern their stability.The potential of AEM systems for defining the geometry of these lens systems in 3D is considered along with an assessment of their value for monitoring variations associated with these ecosystems. The advent of “calibrated” AEM systems and robust inversion tools have given added impetus to their use for environmental monitoring. Spatio-temporal variations are observed in the near surface (top 20m) from a multi-temporal assessment of Clark’s Floodplain, adjacent to the Bookpurnong irrigation area, with co-incident AEM surveys acquired between 2008 and 2015. Spatial changes in ground conductivity, attributed to changing groundwater quality have been observed. The freshwater lens systems appear to have contracted significantly over the last decade. This is attributed, in part, to land use patterns and the development of an irrigation-related groundwater mound on the highlands adjacent to the floodplain, and an increased hydraulic gradient towards the river. The results indicate the geometry of the hyporheic zone may have also changed along the river.

Clustering Field-Based Maize Phenotyping of Plant-Height Growth and Canopy Spectral Dynamics Using a UAV Remote-Sensing Approach.

Phenotyping under field environmental conditions is often considered as a bottleneck in crop breeding. Unmanned aerial vehicle high throughput phenotypic platform (UAV-HTPP) mounted with multi-sensors offers an efficiency, non-invasive, flexible and low-cost solution in large-scale breeding programs compared to ground investigation, especially where measurements are time-sensitive. This study was conducted at the research station of the Xiao Tangshan National Precision Agriculture Research Center of China. Using the UAV-HTPP, RGB and multispectral images were acquired during four critical growth stages of maize. We present a method of extracting plant height (PH) at the plot scale using UAV-HTPP based on the spatial structure of the maize canopy. The core steps of this method are segmentation and spatial Kriging interpolation based on multiple neighboring maximum pixels from multiple plants in a plot. Then, the relationships between the PH extracted from imagery collected using UAV-HTPP and the ground truth were examined. We developed a semi-automated pipeline for extracting, analyzing and evaluating multiple phenotypic traits: canopy cover (CC), normalized vegetation index (NDVI), PH, average growth rate of plant height (AGRPH), and contribution rate of plant height (CRPH). For these traits, we identify genotypic differences and analyze and evaluate dynamics and development trends during different maize growth stages. Furthermore, we introduce a time series data clustering analysis method into breeding programs as a tool to obtain a novel representative trait: typical curve. We classified and named nine types of typical curves of these traits based on curve morphological features. We found that typical curves can detect differences in the genetic background of traits. For the best results, the recognition rate of an NDVI typical curve is 59%, far less than the 82.3% of the CRPH typical curve. Our study provides evidence that the PH trait is among the most heritable and the NDVI trait is among the most easily affected by the external environment in maize.

Shrinkage limit test results and interpretation for clay soils

The shrinkage limit is one of the Atterberg limits and is a fundamental geotechnical parameter used to assess the settlement of engineering soils containing clays, yet is rarely tested for as part of ground investigation. This paper describes shrinkage limit test results on a variety of soils from Britain and overseas obtained using an improved laboratory testing procedure developed at the British Geological Survey. The co-relationships with the other Atterberg limits and with density are explored. In particular, the coincidence of the shrinkage limit with the water content at the peak bulk density achieved in the test is examined. The shrinkage behaviour for undisturbed and remoulded states and a three-way relationship between water content, density and suction are demonstrated. Some tropical residual and highly smectitic soils show a very wide range of shrinkage behaviour, albeit for a small dataset, when compared with the larger dataset of temperate soils tested. Consideration is given to limitations of the new and existing test methods.

Illness and the Politics of Social Suffering: Towards a Critical Research Agenda in Health and Science Studies*

This article analyses some of the emerging problems in the field of social studies at the juncture of the domains of health and science. Building on critical perspectives, namely those hailing from social history, postcolonial studies and collaborative research, it argues for the need to ground investigation on concrete historical forms of social suffering. This implies a multi-scale approach which considers: 1) individual suffering and illness experienced in social interactions; 2) the institutionalised expert translations of suffering into disease; and 3) the political rationales, developed by both local and global stakeholders, which assist in the creation of social environments of health and illness. While illustrations of the theoretical proposals derive mostly from the particular field of mental health, it is argued that their implications may apply to a wider range of themes dealing with health and science issues.

Experience of horizontal directional coring in Hong Kong

Horizontal directional coring is an advanced ground investigation technique which can provide continuous core sampling along a non-linear trajectory, which makes it particularly useful for tunnelling projects. It has been used successfully on several tunnel ground investigations in Hong Kong, with over 15 km of directional cores drilled in the last 10 years. This paper summarises the development of horizontal directional coring techniques and discusses the valuable experience gained and lessons learned from projects in Hong Kong.

Five decades of settlement and subsidence

During the late 1960s and 1970s consideration of land instability in Great Britain was dominated by coal mining-related problems. Subsequently, as the pace of development and infrastructure has increased, there has been a greater awareness regarding collapses due to mining for resources other than coal and also due to karstic features in soluble rocks. This has been highlighted by reference to national and regional studies. In addition, there has been an improvement in the number of recorded occurrences of sinkholes and crown holes. The hazard of ground collapse in certain geological settings, together with the size of collapses and resulting damage to development and infrastructure, has become more evident as case studies have been published. Whereas a range of subsidence triggers are evident, the principal causal agency is usually water from rainfall or leaking utilities. Wider-ranging studies, both in Britain and overseas, have identified ever broader causes of land instability, including those related to glacial and periglacial features, and also uncontrolled groundwater exploitation. This review provides a useful summary of land settlement and subsidence activity to warn practitioners where caution should be applied when carrying out ground investigations and providing design advice.

Engineering geological considerations for the ‘Old’ Beacon Hill Railway Tunnel, Hong Kong Special Administrative Region

Abstract The ‘Old’ Beacon Hill Tunnel was constructed through granite from 1906 to 1910 as part of the Kowloon Canton Railway in the then British colony of Hong Kong. It was the first railway tunnel to be constructed in this region and, at 2.2 km long, longer than any Chinese railway tunnel. Prior to Japanese occupation in December 1941, the British detonated charges to collapse the tunnel to deny its use as an invasion route. Following Japanese defeat in 1945 and return to British government, the tunnel was re-excavated and the damaged sections were supported using steel arches based on Terzaghi's rock mass classification system, which uses geological descriptions to classify loading onto arched tunnel supports. The railway was subsequently realigned during the 1980s and placed in a new tunnel running alongside and west of the ‘Old’ Beacon Hill Tunnel, which was converted to accommodate a pipeline connecting gas supplies. Ground investigations implemented after return of the territory to Chinese sovereignty in July 1997 established that groundwater flow and tunnel stability were influenced by a dyke within the granite, joint set orientation, faulting and weathering as well as the wartime detonations.

Experience from TBM excavation obtained in the Follo Line Project

AbstractIn some projects the selection of TBM is straight forward, but in others all boundary conditions have to be carefully evaluated in order to make the most suitable choice. For underground projects the actual ground conditions remain to certain degree always unknown, regardless of the performed ground investigations. This means specific parameters, which may have significant impact on the project success, might be over‐ or underestimated. Such parameters could be different rock mass properties as well as water ingress. This paper discusses some relevant parameters for TBM selection in hard rock environment, mainly based on the experience gained in the Follo Line Project in Norway. Four double shield TBMs with excavation diameter of 9.96 m are drilling through various kinds of gneisses with banding and lenses of amphibolite and pegmatite. More than 75 % of a total of 36 km have already been excavated with several kilometres of pre‐excavation grouting for reduction of water ingress. Furthermore, potential improvements for TBMs will be proposed in order to make TBMs even more successful.

Identification and implications of the London Clay Formation divisions from an engineering perspective

Historically, engineers frequently viewed the London Clay Formation (LC) as uniform, homogeneous and rather uninteresting. Chris King's seminal work provided a much deeper insight into the characteristics of the LC and how it can be split into divisions, based on the depositional history of the formation and the microfauna present. LC water content profiles were compiled from continuous cores as part of an investigation into variations in tunnelling-induced settlements across St James's Park, allowing distinct zones to be identified. These were found to coincide exactly with the divisions identified by Chris King almost twenty years earlier. Water content profiles can be developed as part of a ground investigation and used to help establish the boundaries between King's divisions. Based on two further water content profiles from Hyde Park and St John's Wood a new methodology for locating the boundaries of the divisions, involving a trend-line for sub-Division A3, is proposed and tested, relevant to conditions in central London. In developing the method, significant differences in the elevation of the divisions between the three sites is observed, suggesting geological processes such as folding or faulting have influenced the LC along the ∼5-km length of the section.Once the boundaries of the LC divisions are known, geotechnical engineers have a greatly improved overall understanding of the ground conditions and how the ground will respond to engineering works such as tunnelling and deep excavations. Broad engineering implications of the divisions are described and discussed, citing case histories where possible.

A two-stage classification approach for the detection of spider mite- infested cotton using UAV multispectral imagery

ABSTRACTSpider mites are important pests that cause severe economic damage to cotton. They feed on underside of leaves, piercing the chloroplast-containing cells, resulting in foliar damage and yield reduction. This paper proposed a two-stage classification approach for mite-infestation detection based on machine learning methods. Two cotton fields were selected for study, and the UAV imagery collection and concurrent ground investigation were conducted on July 20-21th, 2017. Mosaicking and geo-registration were performed on the collected multispectral imagery. Support Vector Machine (SVM) was used for scene classification, and a transferred Convolutional Neural Network (CNN) was applied for mite-infestation identification. Experimental results showed that our method outperformed others in terms of accuracy, which demonstrated that our approach has potential in mite-infestation detection using UAV multispectral imagery.

Slope hazards on the Ethiopian road network

Jointed rock masses, adverse lithological sequences, often deeply-weathered soil profiles, seasonal rainfall, stream erosion and seismicity have created conditions favourable to the development of landslides in many parts of Ethiopia. Large, deep-seated landslides occupy many hillsides and some may date from the late Pleistocene–mid Holocene. Others are more recent and their activity is controlled by rainfall and, in some cases, the effects of land use change and road construction and widening schemes. The road network of Ethiopia has been expanding significantly over recent decades and has been impacted in many areas by reactivated ground movements and new, first-time failures. The Ethiopian Roads Authority (ERA) has undertaken a number of initiatives to combat these problems, including a research programme aimed at developing mitigation designs for 118 locations on the federal road network of the country. Engineering geological mapping formed the cornerstone of the geotechnical investigations, together with targeted trial pitting, drilling and geophysical investigations, that allowed remedial options to be scheduled. Nevertheless, geotechnical uncertainty prevailed at several locations, especially where ground investigation was precluded by budget constraints. A pragmatic approach had to be applied to the construction contract documentation that made provision for confirmatory ground investigation prior to design finalization and geotechnical inspection and interpretation during construction.

Proving a landslide: ground behaviour problems at Pissouri, Cyprus

The residential area of Limnes in Pissouri, SW Cyprus has experienced significant ground behaviour problems since heavy winter rainfall in 2011/2012. These problems have comprised cracking and displacement to the ground, pavements, roads, walls and buildings, leading to the abandonment of the most seriously-affected houses. Nicosia marl comprises the underlying lithology, a material that is associated with volume change upon wetting and drying and has led to foundation problems elsewhere in the country. Various explanations have been given to account for the observed phenomena at Limnes, including the effects of underground water , settlement, slope instability, cyclical shrink–swell, seepage erosion and dissolution. Raised water tables, caused by residential waste-water discharges, applied loads from residential buildings, and inadequate ground investigation and foundation design, are other contributory or causal factors that have been cited. A geomorphological study was undertaken in 2017 and early 2018 that combined field observations with aerial photograph interpretation, and a review of available ground investigation data, to yield an explanation and develop a preliminary ground model. The conclusion drawn was that the Limnes area had been affected by ancient (possibly late Pleistocene–early Holocene) deep-seated failure and that slope instability had subsequently been reactivated at a shallower depth within the failed material as a result of loss of material strength and high water tables. The properties of the Nicosia marl, while important in controlling the behaviour of the ground on a site-by-site basis, were considered to be aggravating factors in the context of the landslide displacement(s) affecting the slope as a whole. InSAR satellite movement monitoring data were analysed for the Limnes area and the outcome vindicated the geomorphological interpretation and helped strengthen the ground model that embodied slope failure as the underlying cause of damage.

3D ground-use optimisation for sustainable urban development planning: A case-study from Earls Court, London, UK

By 2050, almost 70% of the world’s population will live in towns and cities. This places increasing pressure on land to support development whilst minimising environmental impact and providing long-term sustainability. Prior knowledge of the ground at the planning and development stage is needed to assess its suitability to meet planned subsurface uses and avoid subsurface conflicts at an early stage of design.This research tested the development and application of a 3D engineering geological model and its spatial integration with 2D (hydro)geological datasets to support sustainable development decision-making at Earls Court, London, UK. The 3D engineering geological model consists of seven geological layers extending from Made Ground to the top surface of the Chalk Group. The 3D geological model, and 2D datasets derived from it, are combined with 2D geospatial datasets of urban underground space (UUS) indicators to identify potential uses of urban underground space based on its suitability to do so. This is complimented by a qualitative assessment of the potential subsurface interactions between UUS indicator uses and their implications for delivering the sustainability and energy objectives specified in the Earls Court masterplan.Infiltration sustainable drainage systems (SuDS), ground source heat potential and foundation condition potential were chosen as suitable UUS indictors against which to test the outputs of the methodology. Infiltration SuDS potential was assessed using nationally-available (hydro)geological 2D GIS datasets. Ground source heat potential was assessed using national-available 2D datasets and estimates of thermal properties of each geological layer revealed by the 3D geological model. Potentially suitable foundation conditions were assessed using density data from existing ground investigations and depth of suitable geological layers derived from the 3D geological model.The results reveal constraints for the development of rapid infiltration SuDS but opportunities for bespoke design that considers the thickness of overlying permeable sand and gravel. It identifies the susceptibility of the London Clay Formation to potential volume change and ground movement based on an assessment of its plasticity. Closed-loop ground source heat pump opportunities exist depending on site-specific thermal and hydraulic properties and heat exchange design. Opportunities for the use of the Kempton Park Gravel Member for ground source heating and cooling and combined use of thermal regulation and pile design via thermopiles are identified. A qualitative assessment of potential benefits and conflicts between UUS indicator uses reveals that the Kempton Park Gravel Member and London Clay Formation are likely to have the highest, relative, UUS value.The results demonstrate that there is potential to modify the energy and sustainability components of the Earls Court masterplan prior to invasive ground investigation and development. It is further suggested that this approach can be used to compliment research-tested, semi-qualitative means of valuing UUS indicators. The implications of the methodology for mainstreaming UUS into city masterplans is also assessed. It is concluded that opportunities now exist for the integrated 3D and 2D spatial assessment of UUS indicators into city-scale masterplans.

Analysis of Results of Empirical Investigations of Launcher–Missile System Using TEMA Motion Program Environment

The paper presents an analysis of the pictures, recorded from the testing ground investigations, obtained with application of the fast-digital camera Phantom v9.1. The analysis was focused on determination of the kinematics of motion of the launcher-missile system. TEMA Motion program was used for motion analysis of the investigated system. The courses of variability of kinematic values characterising motion of the selected points of the launcher were determined. The results analysis showed that the launcher undergoes the linear displacement (X, Y) and angular one (alpha) that cause significant differences in the flight trajectory of the successively launched missiles

Foundation of 20,000 m3 tanks on soft soils from risk assessment point of view

AbstractIn mid 1980s, the construction of seven smaller tanks having maximum volume of 7,500 m3 and maximum diameter of 25 m for the storage of liquid goods took place in the Port of Koper on the deposit of 28 m thick soft clayey layer. Ground improvement with geosynthetic encased stone columns and preloading was used (Sovinc, Vogrinčič, 1991). Due to satisfactory performance of these tanks, six new large tanks were first supposed to be built in similar way. Due to time constraints and risks involved with much larger tank sizes (V = 20,000 m3 and D = 48.7 m) in combination with variable ground conditions, these new tanks were finally founded on driven tubular steel piles. The paper will present step‐by‐step decision‐making process from the risk management perspective supported by ground investigations, pile load tests and numerical modelling. Finally, the measured behaviour of the new tanks after first 9 years of operation will be shown and practical experience with maintenance of these tanks and connecting pipelines will be shortly presented.

Experimental geothermal monitoring assessing the underground sustainability of GSHP borehole heat exchangers in a protected hydrothermal area: The case study of Ponte Arche (Italian Alps)

An experimental geothermal monitoring, performed on the ground source heat pump (GSHP) system running in a nearly zero energy building (NZEB), has been realized in the protected hydrothermal area of Ponte Arche (Italian Alps), at the request of the competent geological authority. The scope is to assess if a thermal interference could appear between the exploitation of the shallow underground by borehole heat exchangers (BHEs) and nearby thermal baths. Currently, in this area an absolute prohibition for shallow geothermal applications is in force, the area is categorized “potentially subject to geothermal manifestations”. However, in light of new geological and hydrogeological knowledge, supported by long-term monitoring, the protection criterion and constraint geometry could be reviewed. Preliminary to the experimental geothermal monitoring, a detailed ground investigation campaign was performed, including: a geological setting overview based on existing cartography, one continuous core drilling, three downhole geophysical surveys, one thermal response test (TRT). The monitored parameters comprehend the underground temperature at different depths, the outdoor air temperature, and the ground-side heat flow of the GSHP. The collected data are presented and discussed, including considerations about the underground sustainability of the BHE field, and about the real heating and cooling operation of the GSHP ground-side.

Case study: the effective use of non-intrusive techniques to maximize value obtained from traditional methods of site investigation

Many brownfield sites undergoing redevelopment contain a significant number of ground conditions such as buried foundations and structures that may be unknown to the developer or purchaser. Effective ground investigation using geophysical technologies can localize anomalies on site that highlight these features and is then followed by intrusive investigation. This case study describes how a site-wide geophysical survey was used in conjunction with targeted standard intrusive methods to evaluate the extent of remnant buried structures on a brownfield site. The end result provided a more comprehensive understanding of the site than could have been obtained by undertaking intrusive investigations alone. The combination of geophysics and intrusive investigation can provide more valuable information than that gained by using either in isolation.

ASTER Spectral Analysis for Host Rock Associated with Porphyry Copper-molybdenum Mineralization

ABSTRACT This study is an attempt to understand the application of spectral image processing methods to ASTER data for mapping host rock associated with porphyry copper-molybdenum mineralization. The application of remote sensing in identifying variations in surface mineralogy, structural elements, and lithologic contacts can help in identifying such relations. Signatures collected from the Advanced Spaceborne Thermal Emission Reflection Radiometer (ASTER) data is used to map the host rock of Zafarqand area. The study area is located in the central segment of the Urumieh–Dokhtar volcanic belt of Iran. The Urumieh-Dokhtar is a potential zone for exploration of new porphyry copper deposits. Band ratio, band math, false colour composites and principal component analysis techniques are used to refine the different lithologic units in the area. These methods showed the discrimination of acidic igneous rock from intermediate igneous rock and the boundary between igneous rocks using the shortwave infrared bands (SWIR) of ASTER at regional scale. Results have proven to be effective and in accordance with the results of field observations, ore microscopy examination and with reference geological map. In conclusion, the image processing methods used can provide cost-effective information to discover possible locations of porphyry copper and epithermal gold mineralization prior to detailed and costly ground investigations. The extraction of spectral information from ASTER data can produce comprehensive and accurate information for copper and gold resource investigations around the world, including those yet to be discovered.