Building Pit Research Articles

Cutter Soil Mix-Energywall full-scale test experimental setup

The demand for sustainable heat production is growing worldwide [1]. Classical geothermal borehole installations are costly due to the required boring depth and space demands in the urban environment. Shallow geothermal heat exchangers comprised of thermally-activated geostructures in combination with heat pumps (also known as energy geostructures, EGS) offer an interesting alternative due to a combination of functions [2]. 
 This paper focuses on the thermal properties of the CSM (Cutter-Soil-Mix [3]) Energywall; a novel EGS type in which heat exchanger pipes are installed in a cutter-soil-mix wall to thermally activate it. Therefore, the CSM Energywall serves the dual function of supporting the soil/overlying structure and providing geothermal energy for space heating/cooling. A test site has been setup in Amstelveen, the Netherlands, where this system will be tested for a 1 year period (starting March 2023). A test site picture is shown in Figure 1.The goals of the experiment are to evaluate the thermal efficiency of the system and to assess its thermo-mechanical behaviour by means of numerical models valiated against the data collected from site monitoring. In the first part of the forthcoming paper, test setup and experimental results (both from the field and laboratory tests of the CSM material) will be presented. In the second part, the implementation and validation of the numerical models will be described. Lastly, the paper will focus on the suitability of the CSM-Energywall as a sustainable urban heat source, with particular reference to the Netherlands context.
 The following research questions have been defined for the CSM-Energywall experiments:
 
 What is the heat extraction potential of a CSM-Energywall in sandy and in cohesive soils?
 Does thermal activation affect the mechanical properties of the CSM material?
 What is the long term heat production potential of the CSM-Energywall?
 How accurately can the heat extraction potential be predicted using numerical models?
 
 A test setup at Amstelveen (NL) has been built to answer the above research questions. The test site is located in a building pit of 22 x 13m. CSM-walls were built along the pit perimeter, serving both as a soil retaining structure and as a foundation for the superstructure. The CSM wall has a thickness of 0.55m and is reinforced with IPE steel beams. The bottom of the CSM wall has a level of NAP-18.0m (NAP= Normaal Amsterdamse Peil, vertical reference system of the Netherlands). The bottom of the steel IPE beams is at a level of NAP-15.6m. The ground level at the test site is located at NAP-0.7m and the groundwater table at NAP-1.5m. The building pit has an excavation level of NAP-4.70m. Heat exchanger pipe loops with a diameter of 20mm have been connected to the steel beams representing the CSM wall reinforcement (Figure 1). The loops have a depth of NAP-15.0m or NAP-11.0m. Five main groups of loops are connected to the flow distributer. Each group is then split into six subgroups. Each subgroup consists of two thermoactive steel rebars. The test setup will run for the duration of the building construction. Being able to select the geothermal activation of the shallowest or deepest loops, it will be possible to measure the energy output of both the fine-grained layers (with a bottom depth of NAP-11.0m) and the underlying sandy layers. 
 During the tests the following aspects will be monitored:
 
 Flowrate of fluid through the main loops (FTB4700 Flowmeter)
 Temperature of each main group of loops (PT100 thermowell)
 Flowrate and temperature of heat pump inlet/outlet fluid (Kramstrup Energymeter)
 Temperature of the soil (thermistor strings)
 
 CSM material core samples have been taken for laboratory testing. Cyclic thermal loading, unconfined compression strength (UCS) tests, computerize tomography (CT) scan tests and hot disk tests will be conducted on samples taken from different depths. The goal of the laboratory testing is to evaluate:
 
 The thermal properties of CSM material depending on the original insitu soil composition, needed to assess the thermal efficiency of the system.
 The UCS of the CSM material, and its possible dependency on temperature.
 The macroporisy and density distribution of the CSM material, to gain insight into the material composition.
 The influence of thermal cycling on the material’s mesostructure (e.g. porosity and density distribution).
 
 The full-scale experiment is going to be numerically modelled in 3D using the COMSOL Multiphysics Finite Element software. The model will be validated based on the experimental results of the test after 1 year and calibrated using laboratory measured thermal properties of the CSM material. The model will then be extended to predict the long term efficiency of the CSM- Energywall and its thermo-mechanincal behaviour.

Roertunnel: Tunnel elements constructed in building pit for in situ part of tunnel

The construction of the A73 highway from Venlo to Maastricht (the Netherlands) involved the construction of the 2.4 km long, dual two lane Roertunnel near the city of Roermond. The Roertunnel consists of a somewhat deeper part crossing the quite small River Roer and its 1 km wide flood Valley, continued by a 1.4 km long shallow tunnel alongside the southern part of Roermond. The water levels in the River Roer vary from low water (summer conditions) to high water levels and possibly flooding of the Valley (spring conditions). Environmental conditions were severe, prohibiting amongst other for dewatering.The project was tendered the Ministry of Public Works and Water Management (Rijkswaterstaat RWS as a design and build contract. The tender documents included a reference design developed by the client for the crossing of the Roer Valley. This design consisted of a cast in situ piled cut and cover tunnel constructed in a building pit formed by temporary sheet piles and closed off at its bottom by a unreinforced concrete slab supported by tie down piles. This concept was designed to avoid dewatering of the building pit.In view of the ground conditions, an immersed tunnel was a more cost effective solution compared to the proposed reference design. However, an immersed tunnel appeared at a first glance not to be feasible as the small depth and width of the River Roer does not allow transportation of tunnel elements over the River from any remote dry dock, and as a dry dock in the vicinity of the tunnel location could not be created as dewatering was not allowed. The careful analysis of the geotechnical data indicated the local presence of a 5 m thick silt layer of low permeability over a length of 350 m along the tunnel alignment at the eastern side of the Roer Valley. This offered the opportunity to create a dry dock of length of about 350 m along the alignment of the tunnel by means of sheet piles reaching into the silt layer, avoiding any dewatering. The dry dock has been used for the construction of the four immersed elements of a total length of about 600 m in two batches. Finally the dock was used to construct the remaining part of the crossing of the Valley as a cast in situ tunnel.A gravel bed foundation consisting of nine berms per tunnel segment has been preferred above sand flow to mitigate the risk of weakening of loose sand in case of earthquake.The paper describes the concept and the various aspects of the design of the immersed tunnel constructed in a dry dock along the tunnel alignment. A section of the paper is devoted to the interaction of structural design and gravel bed design.

Oberflächensetzung im urbanen Raum – Auswertung der Oberflächensetzungen an Gebäuden infolge komplexer unterirdischer Bauabläufe

AbstractTo relieve congestion on the S‐Bahn main line in Munich (urban railway), a second main line is being built over a length of 10 km, with more than 7 km of tunnels and three new underground stations. These new stations at Hauptbahnhof, Marienhof and Ostbahnhof each have a length of about 250 m and are located at depths of up to 45 m. The stations mostly have a central staircase, which will be constructed using the top‐down method with building pits enclosed by diaphragm walls. The platform tubes subsequently constructed using NATM, with a 40 m wide cross‐section consisting of five tubes, have an overall excavation cross‐section of approx. 450 m2. This paper presents the evaluation of the calculated building settlements due to a construction process comprising groundwater drawdown, building pit construction, platform tubes constructed using NATM, traffic tunnels constructed using TBM, and the exploration and rescue tunnel located between the two traffic tunnels, using the Marienhof West station as an example. To perform the evaluation it is necessary to superpose all settlements arising from the different construction stages for each structure, which in some case are calculated across planners and construction sections. From these superposed calculated settlements, the corresponding angular distortions are calculated according to the type of curvature, i.e. concave type or spandrel type of settlement, and compared with the permissible limit values.

Investigations on the sinking process of large pneumatic caissons

AbstractIn order to keep the port of Amsterdam accessible for ocean‐going ships, a new sea lock is under construction at the town of IJmuiden. The new sea lock will replace one of the nearly 100‐year‐old locks and will be the largest sea lock in the world upon completion. In order to prevent vibrations in the vicinity of the old locks and to prevent the need for deep building pits, the gate chambers are constructed as pneumatic caissons. Due to the open U‐shape of the caissons for the gate chambers, they are particularly vulnerable to torsional deformations that can occur during the sinking process, as a result of differential settlements. This was the main reason the contractor OpenIJ (a joint venture of BAM and VolkerWessels) wanted to get a better insight into the behaviour of the soil during the sinking process in order to control the deformations of the caissons during sinking. Together with the Hamburg University of Technology (TUHH) advanced Finite Element calculations were performed using the Abaqus/Explicit model to get a better understanding of the behaviour of the soil under a caisson during failure of the supporting soil berms. With the results and the lessons learned from the Abaqus analyses, additional analyses were made with Plaxis 2D and the Brinch Hansen method in order to support the sinking process. During the sinking process a real‐time monitoring system helped the operators to keep the deformations of the caissons within tolerances. The monitoring results showed that the soil behaved as predicted and both caissons were successfully sunk to their final position.

Developments in the field of removable anchors

The design of inner-city building pits is a challenging task in geotechnical engineering. Due to rising property prices and the limited vacant plots in urban areas, the installation of building pit support measures is often constrained. Besides rigid systems, struts or anchors are often used to support such building pits. On the one hand, this support is required to come up with an economical design and on the other hand, it is necessary to keep the deformations of adjacent structures within certain limits. In this paper a new approach for the design and the (de-)installation process of removeable anchors is presented. By using a non-explosive cracking agent, a fully removeable anchor has been developed. Laboratory test results have shown, that by filling a pre-installed injection tube with the non-explosive cracking agent, a partial destruction of the grout body and consequently a reduction of the bond along the cement body and the steel tendon can be achieved. As a result, an extraction of the steel tendon is possible.

Permanent sheet pile walls in complex soil conditions Surveillance, monitoring and safety

Kvaernerbyen field F1, also known as Kvaernerdammen, is part of the Kvaernerbyen project in Oslo, Norway. Kvaernerdammen consists of a 7-storey residential complex on an underground parking floor. The south-eastern part of the building cuts into the lower part of a steep slope, with soil conditions consisting of dry crust above firm silty clay, followed by quick clay/sensitive clay above a thin moraine layer over bedrock. Due to existing buildings and constructions further up the slope, the allowable deformations of the building pit during and post construction of Kvaernerdammen had to kept within very tight thresholds. Since the summer of 2017, Cautus Geo AS and Multiconsult Norway AS have been cooperating in “research and development” (R&D) focusing on deformations of sheet pile walls (SPW) in complex ground conditions and all aspects connected to interaction between engineering, monitoring, alerting and safety. Starting with surveillance during the construction period, monitoring a permanent SPW supporting the mentioned slope at Kvaernerdammen, the R&D collaboration was continued between Cautus Geo and Multiconsult with continuous surveillance of the construction for almost 2 years after completion. Throughout the project, all phases of a critical SPW-construction have been evaluated, mainly focusing on the effects of seasonal variations in a “permanent” phase. Observations and experiences made during the project with a comprehensive database derived from geotechnical instrumentation have provided an unusually detailed documentation of the development of the construction after completion. The load cells connected to anchors in two rows on the SPW show a correlation between increasing temperature and increasing anchor force in a permanent phase, most likely due to a volume expansion of the structure. This is an opposite trend to what was observed during the construction phase, where increasing force is recorded in the load cells at decreasing temperature, especially at negative degrees Celsius. The temperature in the load cells is measured to oscillate between positive and negative degrees Celsius only during the construction phase. The load may tend to increase in the upper part of the SPW during heavy rainfall, but of negligible value. Based on a slight change in load and deformation during the permanent phase, the SPW is regarded as a stable and secure construction at Kværnerdammen. For future projects, it is important to be aware that load changes in anchors may be dependent on a well-functioning frost protection.

Quaternary megafauna from the Dnieper alluvium near Kaniv (central Ukraine): Implications for biostratigraphy

Subfossil remains of the Quaternary megafauna from two Ukrainian natural history collections stored at Kaniv Nature Reserve and the National Museum of Natural History NAS of Ukraine were examined. Most of the bones were collected in 1965–1966, in the building pit and the gateway of the Kaniv hydroelectric power plant. The fauna is represented at least by ten taxa (Gulo gulo, Mammuthus trogonterii chosaricus, Mammuthus intermedius, Coelodonta antiquitatis, Megaloceros giganteus, Alces alces, Bison priscus, Cervus elaphus, Capra cf. ibex, and Equus ferus). Skeletal parts are represented mainly by skulls, long bones, horns, and tusks. Based on the species composition of proboscideans, at least part of the faunal assemblage is dated by the end of the Middle Pleistocene (Dnieper Stage = Saale, Warta, MIS 6), but majority of bones could be older or younger (Late Pleistocene and Holocene age) due to the alluvial origin of accumulation.

Information modeling of the construction process (the case study of the construction of a civil building pit)

The paper studies approaches to information modeling of construction processes. The technology of earthworks production is fully mechanized. This feature simplifies construction information modeling procedures. As an example, the construction of a civil building pit is considered. The purpose of the work: to develop a sequence of formation and selection of technological solutions with a minimum cost. Combinatorics and numerical methods were applied. The quantitative values of the source data (productivity and cost) are set by the standards of the Russian Federation. The cost and duration of work were used as the selection criteria. The values of the source data and criteria are given in relative units (relative to the minimum value in the array of source and calculated data). As a result of the research, we obtained sets of machines (excavator and dump trucks) with a minimum cost. A graphic image of the duration and cost for each technological solution of earthworks production, which can be formed using the Russian estimation standards, is obtained.

PESTRÉ SEDIMENTY OTTNANGU V BRNĚ-KOHOUTOVICÍCH

The reddish coloured sediment layers (up to 5 m thick) were found within building pit in the Brno-Kohoutovice on the Libušina třída Avenue (NW part of Brno). These sediments were assigned to the Ottnangian based on characteristic pseudoassociation of microfossils. Smectite or illite/smectite dominates over kaolinite among the clay minerals. Minerals typomorphic for granitoids of the Brno Massif, i.e. epidote, amphibole and altered titanite, absolutely dominate (99 mod. %) within the assemblage of translucent heavy fraction. Minerals like garnet and staurolite which are typical for the Ottnangian sediments in this region, are presented only in accessoric amount. The chemical composition of the studied sediments is located between the chemical composition of granodiorites of the Brno Massif and Neogene clays. Relatively high content of Zr, Hf and HREE, which is interpreted as result of presence of very fine grained zircon in studied sediments, is characteristic. High content of SiO2 and comparatively low contents of Al2O3 and Fe2O3 indicates non-lateritic type of weathering. The chemical composition of studied sediments reflects semiarid to humid paleoclimate that the granitoids of the Brno Massif as parent rock have undergone.

Detecting anomalies in diaphragm walls with electrical resistance measurements

ABSTRACTQuality control of diaphragm walls prior to excavation is often difficult. One technique that can be used to detect anomalies in diaphragm walls involves electrical resistance. Electrical resistance measurements across a diaphragm wall can (within a strict framework) be used to verify the presence of leaks in diaphragm walls as a supplement to crosshole sonic logging. From measurements around a test wall conducted in this study, it is concluded that the detectability of anomalies with electrical resistance decreases exponentially with the increasing distance between the measurement electrodes and the wall. Electrical resistance setups with two and four electrodes have been compared. For usable results, a four‐electrode setup must be used in which the potential electrodes need to be placed very close to the wall (less than 0.2 m away). Based upon the test experience, a field setup for verification of a building pit consisting of diaphragm walls is suggested, as well as a setup for determining the quality of the concrete covering the rebar in quay walls constructed with diaphragm walls.

Simulation and Analysis of the Failure for the Water Stop Curtain of Building Pit in Round Gravel Level

The failure of the water stop curtain is a hot engineering problem which is usually seen in deep building pit constriction. In this paper, the SEEP/W module in Geo-Studio is adopted to simulate and analyze the failure of the water stop curtain and the geological condition in a certain project. The curtain defect existed in the round gravel level and its effect on the filtration is also studied. Finally, the strategies for controlling the quality of the water stop curtain are summarized.

The Research of Ground Deformation Prediction Neural Network Model on City Underground Construction

This paper sees the underground construction shield tunnel and foundation trench as study object. It has analyzed disturbance mechanism and ground deformation mechanism, which were caused by shield tunnel and building pit construction. Through the system analysis of ground deformation influence factor, it has confirmed main influence factors, like geological environment condition of overall consideration, physical parameter and construction technology. And it has established ground deformation prediction model based on neural network. Then it has made sensitivity analysis of affecting ground deformation factor by neural network hierarchical analytical approach.

即時排水型ビルピット設備

ビルピットとは建物の地下にある排水槽のことであり，そこから発生する臭気はビルピット臭気と一般的に呼ばれている．ビルピット臭気の主たる発生要因が，ビルピット内における汚水および汚泥の長時間滞留であることは以前から分かっていた．その対策方法の一つとして即時排水が有効であることも既に明らかであったが，設計手法が確立されていなかった．そこで本報では，即時排水の有効性を検証し，設備の設計手法をまとめた結果を紹介する．

Building Pit Dewatering: Application of Transient Analytic Elements

Analytic elements are well suited for the design of building pit dewatering. Wells and drains can be modeled accurately by analytic elements, both nearby to determine the pumping level and at some distance to verify the targeted drawdown at the building site and to estimate the consequences in the vicinity. The ability to shift locations of wells or drains easily makes the design process very flexible. The temporary pumping has transient effects, for which transient analytic elements may be used. This is illustrated using the free, open-source, object-oriented analytic element simulator Tim(SL) for the design of a building pit dewatering near a canal. Steady calculations are complemented with transient calculations. Finally, the bandwidths of the results are estimated using linear variance analysis.

Presence of Macrolide‐Lincosamide‐Streptogramin B and Tetracycline Antimicrobials in Swine Waste Treatment Processes and Amended Soil

Little is known about the fate of antimicrobials during common agricultural waste handling procedures. To better define the potential scope of this problem, concentrations of antimicrobials throughout the waste treatment process were estimated based on known antimicrobial usage, and the resulting predictions of high antimicrobial concentrations indicated the need for further investigation. Samples from building pits, a solids settling basin, a holding pond, and soil amended with waste treatment byproducts were therefore analyzed for traditional chemical parameters and macrolide, lincosamide, and tetracycline antimicrobials. Substantial improvements in water quality were observed during the treatment process. While the macrolide tylosin was not detected, chlortetracycline, oxytetracycline, and lincomycin were found at high concentrations throughout the waste treatment process. Oxytetracycline and lincomycin were also detected in soil from a field amended with waste treatment byproducts.

Application of steel fibre concrete for underwater concrete slabs

In the heart of Berlin, the area of the Potsdamer Platz is being developed into a new multi-functional town centre. As most of the buildings reach far below the ground-water level, the construction of deep building pits becomes necessary. Due to special underground conditions and environmental protection requirements, sealing injection layers cannot be carried out for the deeper parts of these building pits. The remaining solution is to erect an underwater concrete slab, back-anchored by tension piles. These building pits are of a very irregular shape with extremely high water pressure on the concrete slab. In order to increase the overall safety of this construction, steel fibre concrete instead of plain concrete was used for these slabs, thus leading to a robust and ductile construction. This paper gives a short description of the building method, the tests carried out concerning the load carrying and deformation behaviour of such a slab and the additional tests undertaken on the building site to solve remaining questions about the underwater concreting technology of steel fibre concrete.

Steel Fibre Concrete for Underwater Slabs at Potsdamer Platz

Potsdamer Platz in Berlin is the site of a 70,000 m² development that is creating a new city center, with a myriad of offices, housing, shops, entertainment and recreational facilities. As most of the buildings reach far below the groundwater level, the construction of deep building pits is necessary. Due to underground conditions and environmental protection requirements, sealing injection layers can not be used for the deeper parts of these building pits. The remaining solution is to construct an underwater concrete slab, back anchored by tension piles. These building pits are irregularly shaped, with extremely high water pressure on the concrete slab. In order to increase overall safety, steel fibre concrete has been used to achieve a robust and ductile construction.

Calculation and realization of groundwater lowering installations for large size building pits: Placzek, D Proc Ninth European Conference on Soil Mechanics and Foundation Engineering, Groundwater Effects in Geotechnical Engineering, Dublin, 31 Aug–3 Sept 1987V1, P221–225. Publ Rotterdam: A A Balkema, 1987

Calculation and realization of groundwater lowering installations for large size building pits: Placzek, D Proc Ninth European Conference on Soil Mechanics and Foundation Engineering, Groundwater Effects in Geotechnical Engineering, Dublin, 31 Aug–3 Sept 1987V1, P221–225. Publ Rotterdam: A A Balkema, 1987

Stenhøj ved Tolne, en langdysse i Vendsyssel med nedgravet kammer

The Dolmen Stenhøj by Tolne Prior to the restoration of the long barrow "Stenhøj", situated between Hjørring and Frederikshavn in Vendsyssel, a small excavation was carried out (fig. 1)(1), in which it was established that a stone chamber was erected in a pit in the subsoil. A construction of this kind has not previously been published in connection with stone-built chambers in long barrows (2).The barrow was strongly eroded. The material consisted of homogeneous sand without recognizable turf structure.Chamber and passage. The central part of the chamber had been disturbed by recent stone robbery. Under the disturbance were traces of removed chamber- and passage stone (fig. 1), which with the preserved stones show that the chamber had a rectangular plan with two stones on either side and one stone as a rear wall. The chamber opened by a short passage consisting of a pair of stones. No threshold could be demonstrated. The recent disturbance has removed all traces of an original floor. The inner dimensions of the chamber can therefore be given only approximately as c. 2. 70 X 1.25 m. The absolute height of the undisturbed passage stone (no. 20) and the most northerly undisturbed stone of the chamber (no. 22) was 1.59 and 2.12 m respectively.Outside the chamber were partly intact stone packings (fig. 2-3), and a section through these with interpolated base levels of chamber-, passage- and kerb-stones (fig. 4) shows that chamber, passage and packings were placed in an up to 0,83 m deep pit in the subsoil, whereas the kerb-stones were placed at subsoil level.Kerb-stones: 19 stones were preserved, partly in situ (fig. 1). The extent of the barrow to the north-east was determined by means of clear traces of the holes in which the stones had stood (fig. 1).Investigation outside the kerb-stones: South-east of kerb-stone no. 19 and extending under it was a pit (fig. 1:T) with a minimum diameter of 1.25 m and a depth of about 0.80 m below subsoil level.Secondary structures: At the north-east end of the barrow was a practically circular stone setting (fig. 1 and fig. 5) with two layers of stones. The upper layer contained a fire patch (fig. 1:R) and covered by the bottom layer was an urn cremation pit (fig. 1:AN).Finds and dating: The chamber cannot be dated by means of the finds. It is a variant of main type II (4) and is thus dated to the end of the Early Neolithic or the beginning of the Middle Neolithic.Clearance of the chamber seems to be indicated by 55 potsherds (the majority belonging to the Funnel Beaker culture), found in the modern disturbance and in slipped fill. The sherd frequency was highest outside the kerb and lower towards the chamber itself, where no sherds were found. No traces of offerings on kerb-stones could be demonstrated.Near the bottom of pit T, 4 sherds from the same pot were found (fig. 6), namely a foot-bowl from MN.Ib. Kerb-stone no. 19 was standing in situ above part of pit T.The date of the long barrow itself is problematic. Recent total investigations of long barrows have documented such complex circumstances with respect to the shape of chambers and extensions (5-6), that it is only possible to state on the basis of the partial investigation carried out here that a number of the kerb­stones cannot have been erected before MN.Ib, which is in agreement with other long-barrow datings (7).The secondary structure at the north-east end of the barrow is dated, presumably as a whole, by the clay pot AP (fig. 7) from the urn cremation pit AN. The pot may be dated to the end of the Late Bronze Age.Note on the chamber pit: The pit may be regarded as an expression of a material­ and labour-saving construction technique, for which reason it is described as a "building pit" (8). Analogous construction (9-20) is known from Jutland and Holstein. Barrow chambers of main type I and II and possibly III (4) are represented in this material, which with certainty date the building pits to EN.C and MN.Ib. The chambers in building pits comprise freestanding chambers, chambers without a barrow or covered by only a low round barrow without a kerb and now also chambers in long barrows. The material does not provide a basis for drawing general conclusions on the size, shape and origin of the pits. Further information can be expected, when building pits are looked for in future excavations. Niels Sterum