NL2026238B1

NL2026238B1 - Underground vibration shield element

Info

Publication number: NL2026238B1
Application number: NL2026238A
Authority: NL
Inventors: Ernst Raymond; Pieter Kornelis Van Rijn Markus
Original assignee: Civil City Solutions B V
Priority date: 2020-08-07
Filing date: 2020-08-07
Publication date: 2022-04-08
Also published as: EP4193025A1; WO2022029337A1

Abstract

Underground vibration shield element, configured to be arranged in a shielding orientation in the ground for damping and/or absorbing underground vibrations, comprising a main body comprising a substrate of mineral fibres with a bottom surface to be arranged downwards in the shielding orientation of the shield element, a pressure distribution plate, arranged along a top surface, bottom surface and/or side surface of the main body, configured to distribute ground pressure forces and/or vibration forces over the top, bottom and/or side surface, respectively, and at least one channel extending through the main body, wherein the at least one channel has a bottom opening in the bottom surface of the main body.

Description

P34538NLO0/MVM/MBA Title: Underground vibration shield element The present invention relates to an underground vibration shield element for damping and/or absorbing underground vibrations. The present invention further relates to an underground vibration shield system and to a method for shielding an object from underground vibrations.

Underground vibrations are omnipresent and may for example be caused by a wide range of human activities. Industries, construction works and (heavy) traffic are important causes of underground vibrations.

Underground vibrations may cause nuisance, noise pollution, equipment failure and damage. Therefore, governments are increasingly limiting vibration loads in accordance with the Dutch SBR-guidelines, German DIN 4150 and ISO 2631/2 standards.

An underground vibration may propagate through underground media, such as soil and groundwater. Foundations, infrastructural works and buildings may be affected by vibrational waves. Monumental buildings in inner cities are especially vulnerable, given their traditional construction method, older construction materials, and, often, a location close to a road. Such constructions may already have a reduced integrity in view of their age, and are particularly vibration-prone if built without foundation piles on a weak subsoil, such as loam or clay, as is common in the Netherlands. Older buildings are usually not designed to withstand vibrations caused by the increasing amount of heavy traffic on nearby roads. Therefore, even light vibrations can lead to long-term damage, for example to foundations and masonry.

Additionally, in order to increase road safety, local authorities are taking an increasing number of measures to enforce speed limits. For example, chicanes and speed bumps are installed on roads, which force traffic to change direction and therewith achieve a speed reduction. However, when traffic passes through a chicane or over a speed bump, these direction changes cause additional vibrations.

NL2020761B1 discloses an underground vibration barrier of at least one shield element comprising a substrate of man-made vitreous fibres (MMVF), wherein the at least one shield element is arranged underground in such way that vibrations in the ground are substantially reduced and/or absorbed.

It has, however, been found that such a barrier is vulnerable during handling. Furthermore, it has been found that the vibration damping properties may decrease over time.

It is therefore an object of the present invention to provide an underground vibration shield element that may provide high vibration damping properties that are retained throughout its service life, or at least to provide a usable alternative.

The present invention provides an underground vibration shield element according to claim 1. The underground vibration shield element according to the present invention is configured to be positioned in a shielding orientation in the ground, such that underground vibrations can be damped by the shield element, for example by absorption of the underground vibrations, before the vibrations reach other objects. By damping substantially all and/or a portion of the underground vibrations, nuisance and noise pollution may be reduced and failure and damage of equipment and buildings may be avoided.

The underground vibration shield element is configured to be positioned in a shielding orientation in the ground. The shield element may be arranged in a path along which the underground vibrations to be dampened propagate, for example a path between a vibration source, such as a road surface, and an object that is to be protected from underground vibrations, such as a building. This way, vibrational waves will come in contact with the shield element, and will therefore be dampened by the shield element before reaching the object.

The advantage of the underground vibration shield element according to the present invention is that the underground vibration damping properties of the main body of mineral fibres are enhanced by a pressure distribution plate and at least one channel.

The pressure distribution plate is arranged along a top surface, bottom surface and/or side surface the main body, and is configured to distribute ground pressure forces and/or vibration forces over the top, bottom and/or side surface, respectively. Therewith, the main body may be compressed evenly.

Underground vibrations propagate through the ground by vibrational waves, which comprise local pressure variations, transferred through ground forces by ground material, i.e. soil, such as clay and sand, and by ground water. According to the present invention, the pressure variation transferred by ground material, commonly referred to as grain tension, may be relieved by subsequent compression and expansion of the main body, thereby providing vibration damping. The at least one channel improves vibrational damping as the at least one channel creates an empty space, and therefore increases the amount of air in the main body, which provides isolation and allows compression and expansion of the shield element for absorbing grain tension.

The underground vibration shield element may also absorb pressure variations transferred by ground water, commonly referred to as water tension. By allowing ground water to flow towards open spaces in the main body, the water tension may be reduced. This way, it is prevented that ground water may flow around and/or through the main body, whereby the vibrational wave would be transferred.

Additionally, the at least one channel provides an open space into which water may flow and exert a pressure on main body around the at least one channel for absorbing water tension. As the water may flow freely into the open spaces, and as vibration forces may be exerted on the main body through the at least one channel, pressure variations in ground water are relieved.

Furthermore, the flow of water into the at least one channel will tempararily result in an increased water level in that channel. In case a vibrational wave reaches the shield element from above, for example when the shield element is arranged in a shielding orientation underneath a vibration source, such as a road, the top surface of the main body may be compressed by the vibration. Thus, the decompression of the main body may result in a downward pressure opposite to the upward water pressure, and the forces of the downward compression and upward water pressure are opposite to each other. As the forces cancel out, a smaller resulting force remains and vibrations are damped even further. It seems that this combined effect contributes to the improved vibration damping of an underground vibration shield element according to the invention.

This effect may even be achieved when the vibrational waves reach the pressure distribution plate from another direction with respect to the at least one channel. For example, vibrational waves coming from an inclined or diagonal direction may have a component perpendicular to the upward water pressure.

As a result, less underground vibrations will reach the object and the vibrations that will still reach the object may have a lower amplitude, such that the object to be protected may be subject to less and less severe vibrations. This way, the shield element provides shielding to the object, and nuisance, noise pollution, equipment failure and damage due to underground vibrations may be prevented or at least reduced.

The main body may have any size and/or shape suitable for damping underground vibrations. The main body may advantageously have a rectangular shape with 6 sides that are substantially flat, as such a shape can be manufactured easily and allows to place multiple shield elements against other, side-by side to form a shield system of vibration shield elements. As such, shield elements may be laid side by side in three orthogonal directions, to create multiple layers of shield elements. The number of shield elements in each of the three directions may be adjusted to form a vibration shield having any desired the width, height and number of layers. This way, the properties of the vibration shield may be adapted regarding strength and desired damping properties, using a single type of shield element.

For example, when the shield element comprises a plate element, a longitudinal axis of the plate element may be arranged substantially transverse to the path travelled by the underground vibrations in the shielding orientation, for example transverse, such as perpendicular, to a vibration source. This way, a relatively large surface of the shield element may face the vibration source, such that a large amount of vibrational waves may come into contact with the shield element and be damped therewith.

One of the sides of the main body may also have a special shape that differs from the shape of other sides of the main body. For example, a side may be provided with an inclined shape. An inclined side may be advantageous for the drainage of fluids along the top of the main body. In addition, a special shape can help in the application of top layers. For example, if a road pavement is applied on top of the shield element as a top layer, a camber that may be required on the road surface may already be provided with the main body. In this way, a top layer having a constant layer thickness can be applied on top of the shell element, while still a camber can be created on top of the underground vibration shield element.

The main body comprises a substrate of mineral fibres, forming a type of mineral wool. Mineral wool may also be referred to as mineral fibre or man-made vitreous fibre, and comprise stone wool, slag wool and glass wool. Mineral wools are known to have properties that are advantageous for damping sounds and/or vibrations. It has been found that these properties of mineral wool, for example the compressibility, density and open structure, may contribute to improved vibration absorption that surpasses the vibration absorption of other materials, such as polystyrene, which is commonly available in extruded (XPS) or expanded (EPS).

In an embodiment, the substrate is hydrophobic. Hydrophobic properties may be advantageous to minimize the amount of water absorbed by the shield element. It has surprisingly been found that the shield element exhibits improved shielding properties when a lower amount of water is absorbed in the mineral wool structure. Presumably, water absorption by the shield element displaces insulating air that is enclosed in the mineral wool. Water seems to transfer vibrations more effectively than air and therefore, the presence of water in the mineral wool decreases the vibration shielding properties of the shield element.

Additionally, when the shield element is arranged on an object to be protected, the presence of water may cause moisture absorption and corrosion in the object, for example the foundation of a building, which is usually not desirable as that may cause inconvenience to users and construction problems.

The pressure distribution plate may have any desirable shape. Advantageously, the shape of an inner side of the pressure distribution plate corresponds to the shape of the respective surface of the main body, such that the pressure distribution plate fits over that respective surface, allowing forces and vibrations to be transmitted evenly. Additionally, an even fit may prevent resonance of the plate due to movement with respect to the main body. The pressure distribution plate may comprise any material suitable for distributing vibrations and ground/traffic vibrations and forces over the surface of the main body.

5 Advantageously, the pressure distribution plate is made of a more rigid material than the substrate, such that vibrations may be distributed over the whole surface of the main body by the pressure distribution plate, without substantial deformation of the plate itself. In this way, the vibrations through the plate can be transmitted to the main body, where the vibrations are absorbed by elastic deformation of the substrate.

When the shield element is positioned in the ground, ground forces may act on the surfaces of the main body. Ground pressure may occur due to the ground surrounding the shield element in the shielding orientation, but also due to top layers applied on the shield element. If traffic is present around the shield element, the traffic loads and vibrations can cause additional forces. These forces may be unevenly distributed over the main body. It has been found that this may cause differences in the vibration damping properties of the shield element, such as a local decrease of vibration damping. A pressure distribution plate distributes the ground pressure forces along the surface, such that local differences are avoided.

Furthermore, when a road is constructed on a ground layer on top of the shield element, the continuous traffic load may cause gradual rutting in the shield element. It has been found that rutting causes deformations in the substrate, which form an increasingly weak spot that is susceptible to further deformation, causing further progression of the deformation in the substrate, et cetera. Additionally, an underground vibration shield element may even rupture locally, which may cause sagging of the shield element. A deformed road profile due to rutting or sagging of the shield element may then result in additional traffic vibrations. The plate distributes traffic load outside of the average track width of traffic, so that the forces may be spread over the surface of the main body to prevent rutting therein.

The pressure distribution plate offers the additional advantage that, during the construction of a vibration shield, it provides strength to the shield elements. It has been found that the application of the substrate without protective measures may be susceptible to damage, for example causing tears of dimples in the surfaces of the main body. Damage to the shield element may occur while arranging it in the shielding orientation, during handling, or due to unevenness or sharp obstacles in the ground. Damage may be unwanted if a solid construction, for a road or other infrastructure is required. Damage may also result in uneven vibration damping and may hamper water discharge around the shield element. The pressure distribution plate may comprise a higher rigidity and/or surface hardness than the main body.

Therewith, the pressure distribution plate protects the surface of the main body, and limits bending or twisting of the main body.

The pressure distribution plate may, for example, be a plate formed of a single layer. A plate having a single layer may improve vibration damping compared to a composite material consisting of multiple layers.

In an embodiment, the pressure distribution plate comprises an inner side, arranged along the main body, and an opposite outer side, configured to, in the shielding orientation, be in contact with the ground.

In an embodiment, the outer side is provided with a smooth surface. A smooth surface of the outer side may be advantageous in the case of a vertical shielding orientation, as less vertical ground forces may be exerted on the sheet along this surface than would be the case with a structured surface. In particular, a smooth surface of the outer side may be beneficial for avoiding deformation of the main body in case of a vertical shielding orientation of the underground vibration shield element. .

In an embodiment, the inner side is provided with a smooth surface. A smooth surface of the inner side avoids deformation of the main body. This way, local variations in vibration compressibility of the main body are avoided, which may result in improved vibration damping properties of the underground vibration shield element.

In an embodiment, the pressure distribution plate comprises an inner side, arranged along the main body, and an opposite outer side, configured to, in the shielding orientation, be in contact with the ground, wherein the inner and the outer side are provided with different surfaces. This way, the structure and surface roughness of the surface of the inner and the outer side may be optimised for adherence to another surface, such as the main body, a pressure distribution plate, a cover layer or the ground.

In a further embodiment, the outer side comprises a structured surface with elevated elements that extend transversely from the surface. The elevated elements may, for example extend perpendicular to the surface. A structured surface may be advantageous for the application of coating layers, such as road paving or sand. The structure prevents movement of the coating layer with respect to shield element.

In an embodiment, the elevated elements are provided with drain openings that extend through the elevated elements from one side towards an opposing side. The drain openings may allow fluids to drain sideways between the elevated elements, such that retention of fluids, for example rain water, in between the elevated elements may be limited.

In an embodiment, the underground vibration shield element is provided with through- going openings in a direction perpendicular to the inner surface. The trough-going openings may be fluid open, such that fluids may drain through the through-going openings towards the main body.

In a further embodiment, the pressure distribution plate is arranged on the top and/or bottom surface of the main body, and the through-going openings are arranged in fluid communication with at least one of the top openings and/or bottom openings of the main body. This way, fluids may be drained through the shield element efficiently.

In an embodiment, elevated elements are arranged in groups, wherein groups of elevated elements enclose subregions of the structured surface. In this embodiment, at a first portion of the enclosed subregions, the pressure distribution plate may be provided with through-going openings.

In a further embodiment, a second portion of the enclosed subregions is fluidly connected to the first portion of the enclosed subregions with the drain openings. This way, the trough-going openings do not need to be aligned with the elevated elements.

In an embodiment, the underground vibration shield element comprises two pressure distribution plates arranged on opposite sides of the main body.

The at least one channel may allow fluids to drain out of the main body, through the channel, into the ground. It has been found that, even in the case of a hydrophobic substrate and/or a pressure distribution plate, relatively small amounts of moisture may present in the main body. For example, due to aging, hydrophobic properties of the main body may decline. As a result, small amounts of moisture may fill open spaces in the main body, causing air to be expelled out of the main body and reducing the vibration damping properties thereof. The provision of at least one bottom opening allows this water to drain away, such that the effect of aging of the main body may be overcome or alleviated.

Additionally, water in the underground vibration shield element may freeze, resulting in damage of the substrate, causing breakage of the structure between mineral fibres.

Especially in colder climates, and/or open ground layers, for example permeable layers of road surfacing, this may cause an unwanted decline of vibration damping properties of an underground vibration shield element. By draining fluids, the risk of damage due to frost is at least partially relieved.

Water absorbed by the main body may be drained from the inside of the shield element. Especially when multiple shield elements are arranged adjacently to form an underground vibration shield system, drainage of water around the shield elements may be limited and a channel enables efficient drainage.

Additionally, water can flow into the shield element through the at least one channel. When the at least one channel is partially filled with water, the buoyancy of the shield element may be lower than when the at least one channel is completely filled with air. As such, the shield element will have less tendency to float, and may also be partially placed below a groundwater level in the ground.

In an embodiment, the at least one channel has a top opening in the top surface of the main body, such that the at least one channel runs through the main body from the bottom opening to the top opening. This way, water may be drained from the top surface of the main body through the at least one channel.

In a further embodiment, the top opening and bottom opening are of equal size and shape. This allows placement multiple shield elements adjacent to each other, with adjacent top and bottom openings being aligned with each other.

The cross-sectional surface area of each channel may be constant over a length of the channel. A constant cross-sectional surface area may be beneficial as it provides constant vibration damping properties throughout the shield element.

In an embodiment, a surface area of a cross section of the at least one channel is at least 1%, for example at least 2%, such as at least 5%, of a surface area of the main body in a direction of the cross-section of the at least one channel. The cross section may, for example, be an average cross section of the at least one channel in an axial direction of the atleast one channel. By having a larger surface area, less vibrations may be transferred by the main body, fluid flow through the channels may be enhanced and/or vibration damping of the underground vibration shield element may be improved.

In an embodiment, a volume of the at least one channel is at least 1%, for example at least 2%, such as at least 4% of a volume of the underground vibration shield element. The surface areas and/or volumes mentioned above have been found to provide the shield element with advantageous vibration damping properties.

Open spaces in the main body may be formed by the structure of the mineral fibres in the main body, and/or by the at least one opening. Therefore, an open structure of mineral fibres in the main body may also contribute to vibration damping and/or absorbing properties of the shield element.

In an embodiment, the underground vibration shield element comprises multiple channels. By providing multiple channels, the number, position and orientation of the multiple channels may be optimised for the vibrations to be damped. The compression strength of the main body varies with these properties. For example, application under a road may require a higher strength to withstand traffic loads.

In a further embodiment, the multiple channels are arranged, in the shielding orientation, vertically parallel to each other. Vertical channels may provide vertical stiffness of the underground vibration shield element, which may be advantageous for withstanding traffic loads when a road is to be built above an underground vibration shield element.

The multiple channels may be arranged in a pattern, for example a regular pattern in which the multiple channels are evenly distributed over the main body. An even distribution may provide constant vibration damping properties and water drainage properties throughout the underground vibration shield element. Alternatively, multiple channels or groups of multiple channels may be spaced at equal distances from each other. The multiple channels may be arranged in a pattern over the whole main body or in a particular area of the main body, for example nearby an outer edge of the main body, at two opposite outer edges of the main body, et cetera.

In an embodiment, the underground vibration shield comprises a cover layer that covers at least the bottom opening and/or the top opening.

The cover layer may prevent and/or limit ingress of material into the at least one channel, such that the at least one channel remains substantially open. The cover layer may bea layer arranged on top of the bottom opening to cover the bottom opening, or be arranged in an outer end of the at least one channel, to form a recessed cover in the channel. This way, ingress of material, for example ground material such as sand or clay, or the intrusion of pollution or organisms into the at least one channel may be prevented and the at least one channel remains substantially open. This way, water and air may flow therein, contributing to the advantageous properties of the present invention.

The cover layer may comprise a separate layer, or may be integrally formed in the pressure distribution plate and/or the main body. The cover layer may comprise the main body material, the pressure distribution plate material, and/or another material, for example a natural, sustainable material.

The cover layer may partially or completely surround the main body. In this way, entire sides of the main body can be covered by the covering layer. The covering layer may be attached to the main body by wrapping the main body, without the need for additional fixation means.

In addition or as an alternative, the cover layer may be bonded to the main body, for example be glued thereto. An advantage of bonding is that the movement of the main body in relation to the covering layer may be limited therewith. This way, for example, a shape of the main body may be maintained by the covering layer, and/or alignment of the covering layer may be guaranteed, for example with respect to the at least one channel. As such, creep deformation of the main body and/or misalignment of the covering layer due to traffic or ground forces may be prevented.

The cover layer may provide protection to the main body, in particular when the main body has a softer, less coherent and/or less tear-resistant structure than the covering layer. For example, rupturing or disintegration of the main body, e.g. of a rock wool main body due to rough handling, can be limited as the main body is at least partially held together by the covering layer.

In an embodiment, the cover layer is a fluid-permeable cover layer. An advantage of having a fluid-permeable cover layer is that it may allow water to flow through the cover layer, such that water may flow into and/or be drained out of the main body.

For example, the cover layer may be a geotextile fabric layer. A geotextile fabric is readily available and has been found to offer advantageous properties in terms of durability, water permeability and tear resistance.

The fluid-permeable cover layer may at least partially be arranged in between the between the pressure distribution plate and the main body.

In an embodiment, the underground vibration shield element comprises one or more connectors to connect the underground vibration shield element to an adjacent vibration shield element. This way, the shield elements may cooperate to form a vibration shield such that leaking of vibrations between adjacent plates is avoided or at least reduced. In addition, connecting prevents the movement of a shield element by ground and/or traffic forces.

In a further embodiment, the pressure distribution plates are connected by the one or more connectors. As such, the pressure distribution plates may cooperate to distribute ground forces and vibrations along multiple shield elements. Therewith, an even and advantageous vibration damping may be achieved.

In an embodiment, the connectors extend through the underground vibration shield element in a direction perpendicular to the pressure distribution plate, such that the connectors do not limit movement of the underground vibration shield element .

In an embodiment, the connectors have dimensions corresponding to trough-going opening in the pressure distribution plate. This way, connectors may be attached to and/or detached from the pressure distribution plate through the through-going openings. This may be advantageous, as the amount of connectors required for a solid connection may depend on circumstances as soil type, groundwater level, and expected pressure loads, such as traffic loads.

In an embodiment, the connectors may connect underground vibration shield elements by providing a clamping force between adjacent underground vibration shield elements. This way, a strength of the connection may be further improved.

The present invention further provides an underground vibration shield system, comprising a plurality of underground vibration shield elements arranged in the shielding orientation in the ground to form a row of underground vibration shield elements, for damping and/or absorbing vibrations. By having a plurality of underground vibration shield elements, larger objects may be shielded from vibrations and/or objects may be shielded from larger vibration sources, multiple vibration sources or moving vibration sources. Additionally,

vibrations may be damped and/or absorbed more effectively by a plurality of underground vibration shield elements.

In an embodiment, the plurality of underground vibration shield elements are connected to each other to form a row of connected underground vibration shield elements.

As such, transfer of vibrations in between adjacent underground vibration shield elements may be reduced. Additionally, movements of the underground vibration shield elements with respect to each other may be prevented.

In a further embodiment, the pressure distribution plates of the respective connected underground vibration shield elements are connected to each other, for example by a connector. As such, the pressure distribution plates may cooperate to distribute ground forces and vibrations along multiple shield elements. Therewith, a more even and advantageous vibration damping may be achieved In an embodiment, underground vibration shield elements at outer edges of the row of underground vibration shield elements extend perpendicular to the other underground vibration shield elements of the row of underground vibration shield elements. The other underground vibration shield elements of the row of underground vibration shield elements may, for example, be arranged substantially horizontally, while underground vibration shield elements at outer edges of the row of underground vibration shield elements are arranged vertically to damp vibrations that propagate sideways.

In an embodiment, a second row of underground vibration shield elements is stacked on the row of underground vibration shield elements. By having multiple rows, vibration absorbing and/or damping properties of the underground vibration shield system may be improved.

In a further embodiment, top openings of the row of underground vibration shield elements are in fluid connection with bottom openings of the second row of underground vibration shield elements. This way, continuous channels, for example vertical continuous channels may be formed through which water may flow freely to be drained and/or for vibration damping. This is different from water infiltration, wherein water flows may be slowed down in order to infiltrate the soil gradually.

The underground vibration shield system may, in an embodiment, further comprise a mounting bracket, configured to mount the underground vibration shield elements in a shielding orientation on an object, such as a building. The mounting bracket prevents movement of the shield element with respect to the object due to ground movements. This may be especially advantageous in areas where the ground can move through creep, such as with soft clay or peaty soil. Additionally, a mounting bracket allows the shield elements to be placed in a vertical shield orientation, in which there is relatively little support from the soil.

A further advantage of mounting the underground vibration shield elements to a abuilding, is that it enables the shield elements to function as sheet piling. Usually, a foundation of a building comprises an open space or crawl space for maintenance. As a result of creep of the soil, precipitation and vibrations, the crawl space may fill up with soil material overtime. As a result, the paving around the building may sag and the crawl space becomes less accessible. A mounted vibration shield element may act as a sheet pile wall around the foundation of the building, which separates the crawl space from the soil, and therewith prevents soil material from entering to keep the foundation and/or crawl space accessible.

In an embodiment, the mounting bracket comprises mounting elements, such as pins and/or clamps, extending around a part of the shield element, and configured to mount the underground vibration shield elements in the shielding orientation by delimiting movement of the part of the shield element with respect to the mounting bracket.

In an embodiment, the mounting elements have a predefined thickness, such as less than 30% of the thickness of the main body in a cross section perpendicular to the shielding orientation, for example less than 20%, such as less than 10%. As a thick mounting element may limit compressibility of the main body, a thin mounting element has been found to be advantageous for vibration damping. Additionally, a mounting element surrounding the underground vibration shield element may not be desired as it may transfer underground vibrations.

In an alternative embodiment, the underground vibration shield element may comprise a main body and a pressure distribution plate, without at least one channel. In this embodiment, there is provided an underground shielding element, configured to be arranged in a shielding orientation in the ground for damping and/or absorbing underground vibrations, comprising: a main body comprising a substrate of mineral fibres with a bottom surface to be arranged downwards in the shielding orientation of the shield element, and a pressure distribution plate, arranged along a top surface, bottom surface and/or side surface of the main body, configured to distribute ground pressure forces and/or vibration forces over the top, bottom and/or side surface respectively.

In this alternative embodiment, the underground vibration shield element may be treated to be water repellent, or a water repellent foil may be provided on the underground vibration shield element.

Additionally or alternatively, the pressure distribution plate may have dimensions slightly larger than the respective top surface, bottom surface and/or side surface of the main body along which it is arranged such that when multiple underground vibration shield elements are arranged adjacent to each other, the respective pressure distribution plates of the adjacent underground vibration shield elements may come in contact, while a gap remains the respective adjacent main bodies. Water may be drained trough the remaining gap.

According to another aspect of the invention, a method for shielding an object from underground vibrations is provided, comprising the step of arranging a plurality of underground vibration shield elements according to any of the claims 1-14 in a shielding orientation in the ground, for example in the ground in between an object and a vibration source. This method enables shielding the object from underground vibrations, by damping and/or absorbing vibrations caused by the vibration source, such as a vehicle driving on the road surfacing, with the shield elements.

In an embodiment, the method further comprises the step of connecting the underground vibration shield elements to form a vibration absorbing and/or damping shield system of connected underground vibration shield elements. As such, vibration damping and/or absorption may be improved.

The step of arranging the plurality of shield elements in the shielding orientation may, for example, be followed by a step of covering the plurality of underground vibration shields with a top layer of ground, covering material and/or road surfacing.

In an embodiment, the method comprises the steps of attaching a mounting bracket to an object, such as a building, and positioning the underground vibration shield elements in the mounting bracket for fixing the underground vibration shield elements in a shielding orientation on the object. By fixing to the object, movement with respect to the object may be prevented. The underground vibration shield elements may be mounted to the object, for example be suspended thereon. Alternatively, the underground vibration shield elements may be supported in the soil, while the fixing on the object prevents movement of the underground vibration shield element in the soil.

In a further embodiment, the underground vibration shield element may be fixed on a mounting surface of the object, such that the underground vibration shield element, in the shielding orientation, is oriented with a longitudinal axis parallel to the mounting surface.

In a further or alternative embodiment of the method, the underground vibration shield elements are, in the shielding orientation, at least partially positioned below a groundwater level in the ground.

In an embodiment, the methods further comprises the step of determining a groundwater level in the ground, a maximum pressure load on the underground vibration shield elements in the shielding orientation, and/or characteristics of the vibrations to-be- damped; and selecting a shielding orientation in the ground for the plurality of underground vibration shield elements in dependence of the determined ground water level, soil type, maximum pressure load and/or vibration characteristics.

In an embodiment, the method comprises the step of selecting a number of channels in dependence of the determined ground water level, maximum pressure load, soil type and/or vibration characteristics, wherein the step of arranging a plurality of underground vibration shield elements in a shielding orientation in the ground is performed using vibration shield elements having the selected number of channels.

Further characteristics and advantages of the invention will now be elucidated by a description of the embodiments of the invention, with reference to the accompanying drawings, in which: Figure 1 schematically depicts a disassembled perspective view of an underground vibration shield element according to an embodiment of the invention; Figure 2A schematically depicts a side view of the main body of the underground vibration shield element of Figure 1, along cross section A-A; Figure 2B schematically depicts a top view of the underground vibration shield element of Figure 1, along cross section B-B; Figure 3A schematically depicts a partial perspective view of the pressure distribution plate of Figure 1; Figure 3B schematically depicts a partial perspective view of the pressure distribution plate according to another embodiment of the invention; Figure 4 schematically depicts a disassembled perspective view of an underground vibration shield element according to an embodiment of the invention; Figure 5A schematically depicts a perspective view of the underground vibration shield element of Figure 1, further comprising multiple connectors; Figure 5B schematically depicts a side view of the underground vibration shield element of Figure 5A, along cross section C-C, wherein the underground vibration shield element is connected to adjacent vibration shield elements to form a row of connected underground vibration shield elements; Figure 8 schematically depicts a perspective view of an underground vibration shield system according to an embodiment of the invention; Figure 7 schematically depicts a side view of detailed section S of the pressure distribution plate of Figure 6, when arranged next to an adjacent pressure distribution plate; Figure 8A schematically depicts a side view of a disassembled underground vibration shield element positioned in a shielding orientation in the ground;

Figure 8B schematically depicts a side view of the disassembled underground vibration shield element of Figure 8A, when subject to a vibrational wave; Figure 9A schematically depicts a perspective view of an underground vibration shield system according to an embodiment of the invention; Figure 9B schematically depicts a side view of the underground vibration shield system of Figure 9A, Figure 9C schematically depicts side view of underground vibration shield system according to an embodiment of the invention, when subject to a vibrational wave; Figure 10 schematically depicts a perspective view of a disassembled underground vibration shield system according to an embodiment of the invention; Figure 11 schematically depicts a perspective view of the underground vibration shield system of Figure 10 in a shielding orientation in the ground, when mounting brackets are attached to a building.

Throughout the figures, the same reference numerals are used to refer to corresponding components or to components, which have a corresponding function.

Figures 1, 2A, 2B and 3A schematically depict an underground vibration shield element 1 according to an embodiment of the invention, partially or in its entirety.

The underground vibration shield element 1 is configured to be arranged in a shielding position in the ground for damping and/or absorbing underground vibrations and comprises a main body 2, two pressure distribution plates 3 and at least one channel 4 extending through the main body 2.

The main body 2 comprises a substrate of mineral fibres with a bottom surface 21, a top surface 22 and side surfaces 23. The bottom surface 21 is configured to be arranged downwards in direction D in the shielding orientation. The main body 2 may have a rectangular shape and comprises a substrate of mineral fibres, for example stone wool, such as hydrophobic stone wool.

The pressure distribution plates 3 are arranged on opposite surfaces of the main body 2, along the top 22 and bottom 21 surfaces. The pressure distribution plates 3 are configured to distribute ground pressure forces and/or vibration forces over the respective surfaces, and comprise a relatively rigid material, for example a plastic such as polyethylene.

The pressure distribution plate 3 comprises an inner side 31 arranged along the main body 2. An opposite outer side 32 is configured to, in the shielding orientation, be in contact with the ground, and is provided with a surface that is different from the surface of the inner side 31. The outer side 32 comprises a surface that is structured on a macroscopic scale. The structured surface comprises elevated elements 33, 34 that extend transversely from the surface 21, in particular perpendicular from the surface 21. The elevated elements 33, 34 comprise a set of walls 33 arranged perpendicularly to another set of walls 34. The elevated elements 33, 34 enclose subregions of the outer surface 32. Alternatively, the elevated elements 33, 34 may also be arranged at a distance from each other, to allow water flow between them and/or may extend under an angle as to improve and or decrease resistance of the surface in the ground. The elevated elements 33, 34 have a constant wall thickness, but may also have a varying wall thickness. The elevated elements 33 34 improve stability of the underground vibration shield element 1 in the ground, and may also improve stability of coating layers, such as sand or gravel applied on top of the underground vibration shield element.

The surfaces 31 32 may also be structured on a microscopic scale, such as having a structure that increases surface roughness, which may improve adhesion of the pressure distribution plate 4 on the main 2, for example when glued thereto.

Trough-going openings 35 are provided in the pressure distribution plate 3, in a direction transverse to the inner side 31, in particular perpendicular. The trough-going openings allow water to flow away from the outer side 32 towards the inner side 31 and the main body 2.

The underground vibration shield element 1 comprises multiple channels 4 that extend through the main body and run from the top surface 22 to the bottom surface 21. The channels 4 comprise a bottom opening 41 in the bottom surface 21 and a top opening 42 in the top surface 22. The bottom opening 41 and top opening 42 are of equal circular shape and size.

The channels 4 are arranged, in the shielding orientation, vertically parallel to each other, such that they run in direction D. The channels 4 are evenly distributed over the main body 2 and a surface area of a cross-section of the channels 4 is more than 1%, in particular more than 2%, more in particular more than 4% of the surface area of the main body 2 a direction of the cross-section of the channels 4 and a volume of the at least one channel is more than 1%, in particular more than 2%, more in particular more than 4% of a volume of the underground vibration shield element 1.

Figure 3B schematically depicts a partial perspective view of the pressure distribution plate 3 according to another embodiment of the invention. The pressure distribution plate 3 is provided with elevated elements 33 that extend perpendicular from the outer surface 32. The elevated elements 33 are provided with drain openings 36 that extend through the elevated elements 33 from one side 37 to an opposing side 38 thereof.

Trough-going openings 35 are provided in the outer surface 32, distributed over the outer surface 32, such that at least one of the trough-going openings 35 is provided in at least one first subregion 39. The through-going openings 35 therefore allow for water drainage out of the at least one first subregion 39. Furthermore, the at least one subregion 39 is fluidly connected to at least one second subregion 39’ via the drain openings 36, such that water may be drained out from a second subregions 9’ via a first subregion 39.

Figure 4 schematically depicts a disassembled perspective view of an underground vibration shield element according to an embodiment of the invention; The underground vibration shield element 1 comprises a fluid-permeable cover layer 5, that covers at least the bottom opening and the top opening 42. The cover layer is at least partially arranged in between the pressure distribution plate 3 and the main body 2. The cover layer prevents ingress of ground material and/or cover layers trough the top opening 42 into the at least one channel 4.

The fluid-permeable cover layer 5 is wrapped around main body 2, such that the cover layer surrounds the main body 2 completely, and extends along the whole top surface 22, bottom surface 21 and along the side surfaces 23. In this embodiment, the main body 2 is held together by the cover layer 5, such that a loose or less-coherent substrate may be used in the main body 2.

The pressure distribution plate 3 comprises an inner side 31, arranged along the main body, and an opposite outer side 32, configured to, in the shielding orientation, be in contact with the ground. The outer side 32 is provided with a smooth surface without a microscopically or macroscopically structured surface.

Figure 5A schematically depicts a perspective view of the underground vibration shield 1 element of Figure 1, further comprising multiple connectors 61 for connection to adjacent vibration shield elements 1. The connectors 61 extend through the underground vibration shield element 1 in a direction perpendicular to the pressure distribution plate 3.

The connectors 61 are U-shaped, comprising a base 62 and two legs 63 that extend perpendicularly from the base 62. The legs 63 have a length sufficiently large to protrude through both sides of the underground vibration shield element 1. The legs 63 may be provided with a thread, for example around their respective free outer ends, such that a swivel or nut 64 can be provided thereon to clamp the connectors 61 on the respective adjacent vibration shield elements 1.

A connectors 61 may have dimensions corresponding to the trough-going opening 35 in the pressure distribution plate, such that connectors 61 may be attached and/or detached by sliding through the through-going openings 35. For example, depending on soil type, groundwater level, and expected pressure loads, the number of required connectors 61 may vary. In use, additional connectors 61 may easily be provided by insertion through a trough-

going opening 35.

Upon insertion, the connectors 61 may be fixed by providing a fixation element, for example a washer 64 and a nut 65, on the free outer ends of the legs 62, as shown along cross section C-C in Fig. 5B.

The legs 63 may also extend non-perpendicularly from the base 62, for example at an angle larger than 980 degrees, away from each other. This way, insertion of a leg 63 in an adjacent vibration shield element 1 with another leg 63 already inserted in a vibration shield element 1 may be eased. Furthermore, a washer 64 may be provided with two openings corresponding to the two outer ends of the legs 63 of a connector 61. A distance between the two openings of the washer 64 may be predetermined to correspond to a distance between the two outer ends. Alternatively, the distance between the two openings may be smaller, such that the two outer ends of the legs 63 may be pulled towards each other upon application of the washer 64 over the outer ends. Thus, upon application of the washer, 64, the legs 63 provide a clamping force between adjacent underground vibration shield elements

1. A predetermined clamping force between the adjacent underground vibration shield elements 1, in particular between the pressure distribution plates 3 thereof, may be achieved by selection of distance between the openings in washer 64.

By connecting multiple underground vibration shield elements 1, a row of connected underground vibration shield elements may be formed, which reduces leaking of vibrations between adjacent plates. Additionally, by connecting the pressure distribution plates 3, vibrations and ground pressure forces may be spread along multiple pressure distribution plates 3 of multiple vibration shield elements 1, such that a more even vibration damping may be obtained.

Additionally, underground vibration shield elements may be connected to other objects, such as foundations of buildings or other infrastructural elements.

Figures 6 and 7 schematically depict embodiments of an underground vibration shield system 7 according to an embodiment of the invention. Figure 6 schematically shows two vibration shield elements 1 stacked on top of each other to form a stacked underground vibration shield system of stacked underground vibration shield elements. Top openings of a lower first underground vibration shield element are in fluid connection with bottom openings of a second upper underground vibration shield element. Similarly, a second row of underground vibration shield elements may be stacked on a row of underground vibration shield elements, such that top openings of the row of underground vibration shield elements are in fluid connection with bottom openings of the second row of underground vibration shield elements.

Figure 7 shows section S of the pressure distribution plate 3 in more detail, when two vibration shield elements 1 are arranged next to each other. As shown in Figure 6, one or multiple of the channels 4 may be arranged in a different position, for example diagonally. This may allow to drain water away from the underground vibration shield element 1.

Additionally, the cross section of the channels 4, the top opening 42 or bottom opening may vary, and may for example be square or have any other shape advantageous for vibration damping. Some of the top openings of a lower underground vibration shield element 1 are in fluid connection with bottom openings of an upper underground vibration shield element 1.

The underground vibration shield elements 1 comprise connectors 66, 67 for connection with an adjacent underground vibration shield element 1. The connectors 66, 67 are arranged in the pressure distribution plate 3. Connectors may additionally or alternatively also be arranged in the main body 2 or elsewhere shield element 1. The connectors are shaped as rectangular protrusions 66 and slots 67 arranged in the surfaces of the shield element. Additionally or alternatively, the protrusions 66 and slots 67 may be shaped like snap-fit connectors, dovetail joints, hook-and-loop type fasteners, pin-hole connections or other form-fitted connections. The connectors may also comprise wedges, bolts or other force-fitted connections.

Figures 8A and 8B schematically depict a side view of a disassembled underground vibration shield element positioned in a shielding orientation in the ground 94 before and during a vibrational wave. The underground vibration shield elements are partially positioned below a ground water 95 level in the ground 94. For clarity, the pressure distribution plate 3 and the main body 2 are shown separately in the figures, but may form one integral piece.

The shielding orientation in the ground may be determined before arranging the underground vibration shield element 1 in the ground 94, for example by determining influence of orientation on vibration damping properties.

Additionally, a groundwater level, maximum pressure load on the underground vibration shield elements, for example due to the weight of traffic and/or characteristics of the vibrations to be damped may be determined before arranging the underground vibration shield elements 1 in the shielding orientation in the ground.

The shielding orientation, comprising the inclination, location and height of an underground shielding element, a number of channels 8 a number of pressure distribution plates 3, and a number of underground vibration shield elements 1 to be arranged in the ground adjacent to each other, side by side or on top of each other, may be selected in dependence of the properties determined above.

A vibration may cause a local pressure increase P in the ground 84. The pressure P is transferred to the pressure distribution plate 3 by the ground 94, after which the pressure P is distributed evenly along the top surface of the main body 2 as distributed pressure Q. The pressure P is also transferred to the ground water 95, causing local variations in the ground water 95 level. The channels 4 allow water to rise locally, reducing the pressure P, such that the vibration is damped. Additionally, the rising ground water 95 level in the channels 4 of the main body 2 cause a force F into the substrate of the main body. The distributed pressure Q is directed downward and counteracts the force F in the main body 2, providing further damping of vibrations. Figures 9A, SB and SC schematically depict a perspective view of an underground vibration shield system 7 according to an embodiment of the invention, comprising multiple underground vibration shield elements 1, 1° arranged in a shielding orientation underneath a road 90. The pressure distribution plates of the plurality of underground vibration shield elements form a row of underground vibration shield elements. Underground vibration shield elements 1" at outer edges of the row of underground vibration shield elements extend perpendicular to the other underground vibration shield elements 1 of the row of underground vibration shield elements. The other underground vibration shield elements 1 of the row of underground vibration shield elements are arranged substantially horizontally, while underground vibration shield elements at outer edges of the row of underground vibration shield elements are arranged vertically to damp vibrations that propagate sideways.

By having perpendicular vibration shield elements 1°, vibrations may be damped sideways. The underground vibration shield elements are covered with top layers of ground, covering material and road surfacing. After arranging in the ground, for example between the object and a vibration source, such as underneath a road surface, the underground vibration shield elements may be connected to form a vibration absorbing and/or damping shield system 7 of connected underground vibration shield elements 1. When a vehicle 91 acts as a source of vibrations V, the vibrations V may be damped before reaching an object, such as a vulnerable building.

Figures 10 and 11 schematically depict a perspective view of an underground vibration shield system 7 according to an embodiment of the invention. The underground vibration shield system 7 comprises a mounting bracket 8 configured to fix a vibration shield elements 1, for example from the embodiment of Fig. 4, in the shielding orientation to an object, such as a building 92. A vibration shield element 1 according to Figure 4 may be advantageous as a smooth pressure distribution plate 3 is provided on one side of the main body 2. On another side of the main body 2, no pressure distribution plate 3 is provide, such that the shape of the main body 2 may adapt to the foundation 93 and fit snugly against the foundation 93, even if there are unevenness on the surface of the foundation 93.

The mounting bracket 8 comprises mounting elements 81, arranged to extend around a part of the underground vibration shield elements 1, configured to mount the underground vibration shield elements 1 in the shielding orientation by delimiting movement of the part of the underground vibration shield element 1 with respect to the mounting bracket 8.

The mounting bracket 8 comprises mounting elements 81, such as pins and/or clamps. The mounting bracket 8 comprises a lower rail part and an upper rail part. The mounting elements 81 are configured to extend between the lower and upper rail parts, and may be movable and or removable therefrom. As such, underground vibration shield elements 1 may be provided in between the lower and upper rail parts, after which they may be mounted by the mounting elements 81, extending around a part of the shield elements 1 and configured to mount the underground vibration shield elements 1 in the shielding orientation by delimiting movement of the part of the shield element 1 with respect to the mounting bracket 8.

The mounting elements 81 have a thickness less than 30% of the thickness of the main body 2 in a cross section perpendicular to the shielding orientation, for example less than 20%, such as 10%.

In use, the mounting bracket 8 may first be attached to a mounting surface, such as a foundation 93 of a building 92, after which the underground vibration shield elements 1 may be positioned in the mounting bracket 8 in the shielding orientation, for example in a direction parallel to the mounting surface.

When the building 92 is arranged nearby a road 90, vibrations V may be transferred via the foundation 93 of the building. By attaching the vibration shield system 7, vibrations may be damped before reaching the foundation 93. With the mounting bracket 8, vibration shield elements may be attached to the foundation 93. This method may be easier to install as no repaving of the road surface itself is necessary. Additionally, in the case of a soft soil layer, sinking of the underground vibration shield elements 1 into the ground may be prevented.

Claims

- CONCLUSIONS -

An underground vibration shielding element (1), adapted to be installed in a shielding orientation in the ground for damping and/or absorbing underground vibrations, comprising: a. a main body (2) comprising a substrate of mineral fibers with a lower surface ( 21) to be mounted downward in the shield orientation of the shield element; b. a pressure distribution plate (3) arranged along an upper surface (22), lower surface (21) and/or side surface (23) of the main body (2}, arranged to transmit ground pressure forces and/or vibrational forces over the upper, lower and/or side surfaces (21), respectively , 22, 23), and c) at least one channel (4) extending through the main body (2), the at least one channel (4) having a lower opening (41) in the lower surface (21) of the main body (2).

The underground vibration shield member of claim 1, wherein the at least one channel includes an upper opening in the upper surface of the main body such that the at least one channel extends through the main body from the lower opening to the upper opening.

The underground vibration shield element of claim 1 or 2, further comprising a liquid-permeable cover layer covering at least the lower opening and/or the upper opening.

The underground vibration shield element according to any one of claims 1 to 3, wherein a cross-sectional area of the at least one channel is at least 1%, for example at least 2%, such as at least 4% of a surface area of the main body in a direction of the cross-section of the at least one channel.

Underground vibration shielding element according to any one of the preceding claims, wherein a volume of the at least one channel is at least 1%, for example at least 2%, such as at least 4% of a volume of the subsurface vibration shielding element.

An underground vibration shielding element according to any one of the preceding claims, comprising a plurality of channels.

The underground vibration shielding element of claim 6, wherein the plurality of channels are arranged vertically parallel to each other in the shielding orientation.

The underground vibration shield element according to any one of the preceding claims, further comprising one or more connectors for connecting the underground vibration shield member to an adjacent underground vibration shield member.

The underground vibration shield element according to any one of the preceding claims, wherein the pressure distribution plate comprises an inner side arranged along the main body and an opposite outer side arranged to contact the ground, in the shield orientation, wherein the inner and outer sides of different surfaces are provided.

The underground vibration shield member according to any one of the preceding claims, wherein the pressure distribution plate comprises an inner side arranged along the main body and an opposite outer side arranged to contact, in the shield orientation, the ground, the outer side of a smooth surface. is provided.

The underground vibration shield element of claim 9, wherein the exterior comprises a textured surface with raised elements extending transversely from the surface.

The underground vibration shielding element of claim 11, wherein the raised elements have drainage openings extending through the raised elements.

The underground vibration shielding element according to any one of claims 9-12, wherein the pressure distribution plate is provided with through-openings in a direction perpendicular to the inner side.

The underground vibration shielding element of claims 11 and 13, wherein groups of raised elements enclose sub-regions of the structured surface, wherein at least one of the through-openings is provided in at least a first sub-region, and wherein at least a second fluid sub-region is connected. with the at least one first sub-region via the discharge openings.

The underground vibration shield member according to any one of the preceding claims, wherein the underground vibration shield member comprises two pressure distribution plates arranged on opposite sides of the main body.

An underground vibration shielding element according to any one of the preceding claims, wherein the liquid-permeable cover layer is arranged at least partially between the pressure distribution plate and the main body.

An underground vibration shield system comprising a plurality of subterranean vibration shield elements according to any one of claims 1-18 arranged in the shield orientation in the ground to form a row of subterranean vibration shield members for damping and/or absorbing vibrations.

The underground vibration shielding system of claim 17, wherein the pressure distribution plates of the plurality of subterranean vibration shielding elements in the row of subterranean vibration shielding elements are interconnected.

The underground vibration shielding system of claim 17 or 18, wherein subterranean vibration shielding elements at outer edges of the row of subterranean vibration shielding elements extend perpendicular to the other subsurface vibration shielding elements in the row subsurface vibration shielding elements.

The subterranean vibration shield system of any one of claims 17 to 19, comprising a second row of subterranean vibration shield members stacked on the row of subterranean vibration shield members, upper openings of the row of subterranean vibration shield elements for fluids connected to lower apertures of the second row subterranean fluid. -vibration shielding elements.

21. Underground vibration shielding system according to any one of claims 17-20, comprising a mounting bracket adapted to fix the underground vibration shielding elements to an object, such as a building.

The underground vibration shielding system of claim 21, wherein the mounting bracket includes mounting elements, such as pins and/or clamps, extending around a portion of the shielding members, and adapted to secure the subsurface vibration shielding members in the shielding orientation by limiting movement. of the part of the shield element relative to the mounting bracket.

A method of shielding an object from subterranean vibrations, comprising the step of arranging a plurality of subsurface vibration shielding elements according to any one of claims 1-15 in a shielding orientation in the ground between an object and a vibration source.

The method of shielding an object from subterranean vibrations according to claim 23, comprising the step of connecting the subterranean vibration shielding elements together to form a row of connected subsurface vibration shielding elements.

A method for shielding an object from underground vibrations according to claim 23 or 24, further comprising the steps of: a. attaching a mounting bracket to an object, such as a building; b. positioning the subterranean vibration shield members in the mounting bracket to secure the subterranean vibration shield members to the object in the shield orientation.

A method for shielding an object from subterranean vibrations according to any one of claims 23-25, comprising the step of positioning the subsurface vibration shielding element at least partially below a groundwater level in the ground.

A method of shielding an object from subsurface vibrations according to any one of claims 23-26, further comprising the steps of: a. determining a groundwater level in the ground, a maximum pressure load on the subsurface vibration shielding elements in the shielding orientation, soil type and/or characteristics of the vibrations to be damped; and B. selecting a position for the plurality of underground vibration shielding elements depending on the determined groundwater level, maximum pressure load, soil type and/or vibration characteristics.

The method of shielding an object from subsurface vibrations according to claim 27, further comprising the step of:

a. selecting a number of channels depending on the determined groundwater level, maximum pressure load, soil type and/or vibration characteristics, wherein the step of installing several underground

anti-vibration elements in a shield orientation is performed using a combination of anti-vibration elements with the selected number of channels.