A pile module for a rock pile foundation system
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2026-01-15
- Publication Date
- 2026-08-13
Smart Images
Figure SE2026010007_13082026_PF_FP_ABST
Abstract
Description
[0001] A pile module for a rock pile foundation system, a rock pile foundation system and a method for installing a rock pile foundation system
[0002] Technical field
[0003] The present disclosure relates to a pile module for a rock pile foundation system, a rock pile foundation system and a method for installing a rock pile foundation system. More specifically, the disclosure relates to a pile module for a rock pile foundation system, a rock pile foundation system and a method for installing a rock pile foundation system as defined in the introductory parts of the independent claims.
[0004] Background art
[0005] When constructing foundations in bedrock, toe-bearing pile systems are typically used. Such toe-bearing pile systems often comprises steel piles configured to transfer compressive loads. To handle tensile loads, also called uplift forces, toe-bearing pile systems are typically reinforced using high-strength steel bars that run the length of the pile system and beyond. The steel bar may be hollow or solid and typically extends several meters beyond the toe of the pile and is grouted into the bedrock. Using such steel bars may cause a problem when executing foundations since it requires two separate drilling and installation procedures, one for the steel pile and another for the steel bar. The steel pile is typically installed first, and the steel bar is subsequently positioned inside the steel pile and is lowered into the grout in the bedrock borehole. Using a steel bar could be problematic during winter months since it is generally advised not to insert components with sub-zero temperatures into boreholes, to avoid cracking in the grout. Thus, during winter months, the steel bar will have to be heated to maintain an acceptable temperature before being inserted into the borehole. This is a problem both in terms of energy consumption and in terms of the extra space required to achieve an acceptable temperature of the steel bar. Furthermore, the length of the steel bar also means that a large amount of steel is used. Known solutions using toe-bearing steel piles and steel bars are thus disadvantageous both from a time and cost perspective and from a sustainability perspective.
[0006] There is thus a need to develop a solution for rock pile foundation systems, which facilitates the installation and ensures optimal performance.It is an object of the present disclosure to mitigate, alleviate or eliminate one or more of the above-identified deficiencies and disadvantages in the prior art and solve at least one of the above-mentioned problems.
[0007] An object of the present invention is thus to achieve a pile module for a rock pile foundation system, which facilitates installation of the system, and reduces the resource consumption, the time for execution and thereby the costs.
[0008] Another object of the present invention is to achieve an improved rock pile foundation system and method for installing the rock pile foundation system which reduces resource consumption, the time for execution and the costs.
[0009] According to a first aspect of the present disclosure, there is provided a pile module for a rock pile foundation system, the pile module being configured to transfer compressive and tensile loads. The pile module comprises a tubular body with an open first end and an open second end, wherein the pile module is connectable to a pile element at the first end and is configured to transfer compressive loads at the second end. The tubular body comprises a circumferential wall forming an inner space, wherein the circumferential wall comprises at least one opening for discharging cement grout from the inner space to a borehole in the bedrock and thereby securing the pile module.
[0010] The pile module according to the present disclosure being connectable to a pile element at the first end may have a similar outer diameter as the pile element. The pile module will, by means of its configuration, be able to transfer the applied compressive loads to the second end of the tubular body. The tubular body will thus be arranged with the second end facing in direction of the bottom of the borehole. The pile module comprising at least one opening for discharging a cement grout enables injection of cement grout under pressure, from inside the pile module into the space formed between the pile module and the borehole wall. The pile module will this way be grouted into the borehole and will thereby be able to withstand compressive and tensile (uplifting) loads on the system. The configuration of the tubular body, and specifically the shaft surface of the circumferential wall, will enable the pile module to withstand the tensile loads through the shaft resistance between the pile module and the cement grout. The pile module may thus be seen as an extension of the pile elements of the pile system and can handle both compressive and tensile loads. Thus, by using the pile module, no steel bars are required. The open second end of the pile module is suitablyconfigured for connection to a separate drill element. The pile module is configured to be advanced through the borehole simultaneously with the drilling of the borehole. Installation is facilitated since only one drilling and installation procedure is required and less resources will be used. The pile module will be inserted into the borehole prior to injecting the cement grout and will thereby have the same temperature as in the borehole when the cement grout is injected. The temperature in the bedrock borehole is typically above zero and there will thus be no need for heating the pile module before installation. By means of the pile module according to the present disclosure, a more time efficient, cost efficient and more sustainable solution is achieved. The pile module will form part of a rock pile foundation system and will typically be connected to a first of a plurality of pile elements. It is to be understood that the pile module may be connected to another pile module. Thus, multiple pile modules may be connected to each other. At least one pile module will then be connected to a pile element at the first end. The plurality of pile elements together forms a pile. The pile elements may be connected to each other by means of mechanical joints, couplings or welding. The last pile element of the pile is configured to be connected to a bearing plate and a structure, such as a building, a wind powerplant, or a transmission tower.
[0011] The tubular body of the pile module may be referred to as a pipe section. The wall thickness of the circumferential wall of the pile module may be between 10 mm and 50 mm, more preferably, between 10 and 20 mm.
[0012] The cement grout to be discharged through the at least one opening and securing the pile module in the borehole may be a mixture of cement, sand, water and / or chemicals. The cement grout may also be referred to as slurry, cement suspension or mortar. The cement grout is injected into the inner space of the tubular body and will be discharged through the at least one opening in the circumferential wall.
[0013] The at least one opening may have a diameter between 1 mm and 10 mm, preferably between 3 mm and 4 mm. The at least one opening may have a cylindrical shape and / or a conical shape. Alternatively, the at least one opening may be a slit or a slot. A conically shaped opening tapers from a wider diameter at the entrance to a narrower diameter at the end or vice versa. Alternatively, the at least one opening may be chamfered at the other side of the circumferential wall. The at least one opening may thus have a cone-like section, with the wider diameter at the outer side of the circumferential wall. The conical opening is defined by an axis of symmetry and an angle between the walls, referred to as the apex angle or included angle. This angle is measured as the angle formed between the sloping walls of the conicalsurface, intersecting at the axis of symmetry. The apex angle determines the degree of taper and is specified as the total angle subtended between opposing walls of the conical surface. The apex angle of the at least one opening may be between 50° and 70°, more preferably between 55° and 65°. The apex angle of the at least one opening is suitably chosen so that the cement grout is distributed optimally into the borehole in the bedrock. Having a conical opening for discharging cement grout allows for efficient grout distribution, enhancing the bearing capacity of the foundation. The at least one opening may additionally or alternatively be chamfered or conical at the inner side of the circumferential wall.
[0014] The tubular body may comprise a plurality of openings distributed along the circumferential wall. The openings may be evenly distributed along the length of the tubular body, the length of the tubular body extending from the first end to the second end. The openings may thus be arranged at a predetermined distance from each other along the length of the tubular body. Additionally or alternatively, the openings may be evenly distributed along the circumference of the tubular body. The openings may be arranged in a predetermined pattern. The openings may be arranged at the upper part of the tubular body, closest to the first end. Additionally or alternatively, the openings may be arranged at the lower part of the tubular body, closest to the second end. In some examples, the openings are arranged at a predetermined angle in relation to each other along the circumference of the tubular body. In an example, the openings are arranged at an angle of 120° from each other at a predetermined first distance from the first end, forming a first set of openings. At a second distance from the first end, the pattern of the openings has been displaced 30° relative to the first set of openings, forming a second set of openings, and so on. Thus, for each level of openings, the openings may be displaced 30° relative to the adjacent level of openings. The openings may alternatively be randomly distributed along the length of the tubular body. Comprising a plurality of openings ensures uniform grout distribution, which improves the bonding between the pile module and the surrounding bedrock, leading to increased structural integrity.
[0015] According to an example, the circumferential wall comprises a machined surface to increase the shaft resistance between the pile module and the cement grout. The machined surface is a deliberately engineered or modified area designed to increase shaft resistance between the pile module and the cement grout. The machined surface may have different types of textural features such as grooves, ridges, dimples, or patterns. The machined surface enhances the shaft resistance, providing better load transfer and reducing the risk of shear failure under tensile loads.In some examples of the present disclosure, the pile module further comprises at least one protrusion on an outer side of the circumferential wall. The pile module may comprise a plurality of protrusions, wherein the protrusions are evenly distributed along the length of the circumferential wall. The protrusions may be arranged in a predetermined pattern along the length of the tubular body. The protrusions may alternatively be randomly distributed along the length of the tubular body. In some examples, the tubular body comprises protrusions along a part of the length of the tubular body, preferably along at least a third of the length of the tubular body. The protrusions are suitably arranged along at least a third of the length, closest to the second end of the tubular body. With at least one protrusion on the circumferential wall, the contact surface between the pile module and the surrounding cement grout is increased. This way, the mechanical interlock with the cement grout is increased, further enhancing the pile module's ability to resist tensile forces.
[0016] The at least one protrusion may be a circumferential protrusion and may thus encircle the tubular body. Alternatively, the at least one protrusion is a protruding bump, shoulder, ridge or similar. The at least one protrusion may protrude 0,1-1 cm from the circumferential wall. The at least one protrusion may have a height between 0,1-1 cm in the length direction of the tubular body.
[0017] The at least one protrusion may be formed by machining or milling the circumferential wall. Alternatively, the at least one protrusion may be formed by welding or attaching rivets or screws.
[0018] The pile module may be designed to fit a micro-pile system. This means that the pile module should have an outer diameter which is less than 300 mm. Alternatively, the pile module has an outer diameter which is larger than 300 mm. The diameter of the pile module and the thickness of the circumferential wall may be chosen depending on the loads applied on the system and the dimensions of the pile element of the system. It is to be understood that the wall thickness of the tubular body can be thinner than the wall thickness of the pile elements.
[0019] The pile module may have a length extending between the first end and the second end, wherein the length is within the range of 0,5-6 meters, preferably between 1-2 meters. Compared to long steel bars of several meters, the pile module of a much shorter length will require significantly less material. The pile module will thus provide a more sustainable and cost-efficient solution. The length of the pile module is suitably chosen depending on the tensile loads the pile module is expected to withstand. As previously described, multiple pilemodules can also be connected to each other to increase the ability to withstand tensile loads. It has, for example, been confirmed by performed tests that a pile module having a length of approximately 1,5 meters and a diameter of 170 mm can withstand tensile forces in the order of 2000 kN.
[0020] The first end of the tubular body of the pile module may comprise threads for connection with a pile element. In order to connect the pile module to a first pile element of the pile, the first end of the tubular body may comprise threads. The connecting pile element may therefore also comprise threads and the pile module and the pile element are connected by means of a threaded coupling or sleeve overlapping the pile element end and the first end of the pile module. Alternatively, the first end of the tubular body is screwed into the pile element or vice versa and thus engages with threads in the pile element. Alternatively, the first end of the tubular body is tapered for welded connection with a pile element. It is to be understood that for a welded connection between the pile module and the pile element, the pile element and / or the pile module may have a tapered, bevelled or chamfered end. The first end of the pile module and the pile element are typically arranged in abutment and are subsequently welded together along the joint. It is to be understood that the pile module and the pile element may be connected using butt welding, but the welding may be performed using any other welding technique. These connection options provide flexibility in installation, allowing for secure and reliable attachment to various types of pile elements.
[0021] According to a second aspect of the present disclosure, there is provided a rock pile foundation system comprising: at least one pile including at least one pile element, and at least one pile module according to the first aspect. The first end of the at least one pile module is connected to the at least one pile element. The rock pile foundation system may comprise a plurality of piles and each pile may comprise a plurality of pile elements connected to each other. Furthermore, each pile may comprise a plurality of pile modules connected to each other. Thus, at least one pile module may be connected to a pile element at the first end, and optionally to another pile module at the second end.
[0022] The system may be a micro-pile system. This means that the at least one pile element and the at least one pile module each have an outer diameter which is less than 300 mm.
[0023] The rock pile foundation system may further comprise a drill element connected to the second end of the at least one pile module. The drill element may be a coupling element for connection to a drill bit or it may be a drill bit. The drill bit may comprise a pilot bit and a ring bit. When the pile module with the drill bit has reached its desired position in the bedrock, thepilot bit is typically removed from the pile module to be reused. The pilot bit is typically pulled up through the pile module and the pile elements. The ring bit will remain attached to the pile module in the borehole. The compressive loads will thus be transferred to the second end of the pile module and on to the ring bit when the construction is ready. The ring bit typically has a larger diameter than the pile module and will thus generate a borehole with a larger diameter than the outer diameter of the pile module and the pile elements. In some examples, the whole drill bit is removed after drilling, or the whole drill bit remains in the borehole.
[0024] It is to be understood that the pile module as disclosed herein may be arranged at different positions or elevations within a pile. The pile module may for example be arranged at a position in the pile that is above the bedrock. Thus, the pile module may be arranged at a position in the pile that is positioned in soil. During drilling and installation of a pile foundation system, a gap is formed between the pile and the soil. Water and contaminations can thereby move vertically along the pile, which may not be desirable. Such gap typically disappears naturally after some time due to soil reconsolidation. However, by using a pile module as disclosed herein at a higher position in the pile, the pile module can also provide the function of sealing the gap between the soil and the pile by means of grouting. A quicker and more reliable sealing is thereby achieved.
[0025] The pile module may also be connected to the toe of a steel pipe forming part of a steel pipe pile wall in the bedrock. A steel pipe pile wall comprises a plurality of adjacent elongated steel pipes (tubular piles) joined sequentially via longitudinal interlocks to form a continuous barrier. The installation process typically involves advancing the steel pipes one at a time in a linear direction. It is common practice to drill the steel pipe pile wall into bedrock to facilitate excavation down to the bedrock level or deeper. Typically, such operations require drilling into the bedrock situated below the groundwater table (phreatic surface). When a sequence of steel pipes is drilled into the bedrock, a continuous channel or slit is effectively cut into the bedrock. This channel creates a pathway for groundwater migration, leading to leakage both longitudinally along the wall and transversely across the wall. To mitigate this, conventional methods employ grouting through the vertical pile interlocks. However, despite strict regulatory requirements for watertightness, this conventional method frequently fails to achieve a complete seal, resulting in persistent leakage.By attaching a pile module as disclosed herein at the distal end (toe) of the steel pipes, the sealing performance can be improved. The pile module may be attached to the steel pipes by for example welding. The pile modules will allow for the injection of grout in more directions and levels, and the grout will effectively cut off leakage pathways in both the longitudinal and transverse directions relative to the wall axis, thereby providing a superior seal compared to conventional interlock grouting.
[0026] According to a third aspect of the present disclosure, there is provided a method for installing a rock pile foundation system according to the second aspect in the bedrock, the method comprising the steps of: drilling a borehole through the ground and into the bedrock while simultaneously advancing the at least one pile and pile module through the borehole until the pile module has reached a desired position in the bedrock, and pumping cement grout through the rock pile foundation system with a pressure so that the cement grout is discharged through the at least one opening in the pile module to the surrounding borehole in the bedrock. Typically, as the borehole gets deeper and deeper, more pile elements are connected to the pile. The method according to the present disclosure will only require one drilling operation and thus allows for efficient drilling and grouting, streamlining the installation process and ensuring optimal grout placement.
[0027] The step of drilling the borehole may be performed using a top hammer or a down the hole (DTH) hammer. The top hammer is installed on top of the pile being installed whereas the DTH hammer is installed at the bottom of the pile module. The DTH hammer is powered by compressed air or water driving a piston which strikes the drill bit.
[0028] The step of drilling the borehole may comprise the step of connecting a drill element, such as a drill bit, to the second end of the pile module. The drill element may be connected to the pile module by welding, or it may be screwed onto the pile module. The pile module may thus comprise threads at the second end of the tubular body. It is to be understood that the pile module may comprise threads at the second end to enable connection to a drill element and / or to another pile module.
[0029] After the borehole is drilled, the method may comprise removing the drill bit or at least a part of the drill bit. In the event that the drill bit comprises a pilot bit and a ring bit, the pilot bit is removed from the borehole and the rock pile foundation system. The ring bit attached to the pile module may be left in the borehole. The ring bit may have a diameter that is larger than the outer diameter of the pile module so that a space is formed between the pile module and the bedrock. The diameter of the drill bit may be at least 30 mm larger than the diameterof the pile module, thereby forming a space of at least 15 mm between the pile module and the wall of the borehole. The depth of the borehole in the bedrock may be within the range of 0,5-6 meters, preferably between 1-2 meters, depending on the expected tensile loads. It is to be understood that the pile module may be inserted into the bedrock and the pile elements may be surrounded by soil. In some examples, the pile element that is connected to the pile module may at least partly be inserted into the bedrock.
[0030] The step of pumping cement grout through the pile system may involve mixing the cement grout so that the cement grout has the correct characteristics depending on the intended use or the characteristics of the bedrock. Furthermore, the pumping is performed with a pressure higher than the hydrostatic pressure.
[0031] The step of pumping the cement grout may further comprise inserting an injection arrangement for injecting the cement grout. The injection arrangement may be part of the rock pile foundation system.
[0032] The injection arrangement may comprise a pipe or a hose or a combination of pipe and hose, which is inserted through the pile elements and the pile module. The injection arrangement may comprise a pipe portion configured to be inserted first through the pile and is configured to be positioned inside the pile module, and a hose portion configured to be positioned inside the pile elements. The cement grout is thus poured into the hose and / or pipe of the injection arrangement and is thereby lead through the pile elements all the way down to the pile module at the bottom of the borehole. The injection arrangement comprises at least one aperture in the pipe or hose, preferably at the end closest to the drill bit. The cement grout will enter the inner space of the tubular body through the aperture, and when the pile module fills up with cement grout it will be discharged through the at least one opening of the tubular body. The injection arrangement may further comprise a stop plate at the end closest to the bottom of the borehole, the stop plate being configured to prevent the cement grout to leave the pile module via second end.
[0033] The step of inserting the injection arrangement may further comprise arranging an inflatable manchette at the first end of the pile module, to prevent cement grout from leaving the pile module through the first end. The manchette will surround the hose and / or pipe of the injection arrangement and will block the first end of the tubular body so that the pressure builds up inside the pile module when it gets filled with cement grout. This way, the cement grout will be discharged through the at least one opening with a higher pressure and fill the space between the tubular body and the bedrock.The method may also comprise removing the injection arrangement from the pile system after the cement grout has been injected.
[0034] Brief descriptions of the drawings
[0035] The above objects, as well as additional objects, features and advantages of the present disclosure, will be more fully appreciated by reference to the following illustrative and non-limiting detailed description of example embodiments of the present disclosure, when taken in conjunction with the accompanying drawings.
[0036] Figure 1 schematically illustrates a rock pile foundation system according to an example of the present invention.
[0037] Figures 2a-d schematically illustrate a pile module according to examples of the present invention.
[0038] Figure 3 schematically illustrates a cross-section of a pile module according to an example of the present invention.
[0039] Figure 4 schematically illustrates a rock pile foundation system according to an example of the present invention.
[0040] Figure 5 schematically illustrates details of a rock pile foundation system according to an example of the present invention.
[0041] Figure 6 schematically illustrates details of a rock pile foundation system according to an example of the present invention.
[0042] Figure 7 schematically illustrates a method for installing a rock pile foundation system according to the present invention.
[0043] Detailed description
[0044] The present invention will become apparent from the detailed description given below. The detailed description and specific examples disclose preferred embodiments of the disclosure by way of illustration only. Those skilled in the art understand from guidance in thedetailed description that changes and modifications may be made within the scope of the disclosure.
[0045] Figure 1 shows a rock pile foundation system 500 according to an example of the present disclosure. The rock pile foundation system 500 may herein be referred to as the pile system 500. The pile system 500 is thus configured to be used for foundations in bedrock 50. The pile system 500 is configured to be installed in drilled boreholes 10 extending through soil 40 and into the bedrock 50. The pile system 500 comprises at least one pile 510 including at least one pile element 520, and at least one pile module 100. The pile module 100 is configured to transfer compressive and tensile loads acting on the pile system 500. The pile module 100 comprises a tubular body 110 with an open first end 112 and an open second end 114. The pile module 100 comprises a circumferential wall 120 forming an inner space 124. Furthermore, the pile module 100 comprises at least one opening 130 through which cement grout 20 is configured to be discharged, from the inner space 124 of the tubular body 110 to the space between the pile module 100 and the rock wall 11 of the borehole 10. This way, the pile module 100 and the pile system 500 is secured in the bedrock 50. The pile system 500 is designed to provide a stable foundation by integrating its components effectively.
[0046] The tubular body 110 of the pile module 100 is a hollow structure allowing for the insertion and removal of other components. The circumferential wall 120 defines an outer boundary of the tubular body 110, enclosing the inner space 124.
[0047] The at least one opening 130 is located in the circumferential wall 120 of the tubular body 110. This opening 130 serves as an excess point for cement grout 20 to flow into the borehole 10 in the bedrock 50, ensuring that the pile module 100 is securely fixed in place.
[0048] The pile system 500 may further comprise a drill element 400 connected to the second end 114 of the tubular body 110 of the pile module 100. The drill element 400 may be a drill bit used to penetrate the ground, creating a deeper cavity for the pile system 500. The drill bit 400 facilitates the installation of the pile system 500 by ensuring that the pile module 100 can reach the desired depth for optimal stability and load-bearing capacity. At least part of the drill bit 400 may be removed once the pile system 500 is correctly positioned in the bedrock 50.
[0049] The at least one pile 510 with its pile element 520 serves as the primary structural element of the pile system 500, providing the required support for the foundation of a structure. The pile element 520 is connected to the open first end 112 of the tubular body110. The pile 510 is designed to withstand significant compressive loads, transferring these loads from the structure above to the soil 40 and / or bedrock 50 below via the pile module 100, ensuring the stability and integrity of the complete foundation system.
[0050] Figures 2a-d schematically illustrate a pile module 100 according to examples of the present invention. The pile module 100 is configured as disclosed in Figure 1. The pile module 100 thus comprises a tubular body 110 with a circumferential wall 120, an open first end 112 and an open second end 114 as previously described. The tubular body 110 is a cylindrical structure designed to provide a robust framework for various applications. The tubular body 110 is typically constructed from durable materials to withstand environmental and operational stresses. The pile module 100 typically comprises steel.
[0051] In Figure 2a, the pile module 100 comprises a machined surface 122 on the circumferential wall 120 and a plurality of openings 130 for the cement grout. The machined surface 122 is a precisely crafted area on the tubular body 110. This surface 122 is engineered to increase the shaft resistance between the pile module 100 and the cement grout. The machined surface 122 may comprise a pattern.
[0052] The openings 130 are strategically positioned along the length L of the tubular body 110. The openings 130 are designed to optimize flow and minimize any potential disruptions to the system's 500 performance.
[0053] Figure 2b shows an example where the pile module 100 comprises a plurality of openings 130 for the cement grout but they are primarily positioned on the lower half of the pile module 100, the half of the tubular body 110 that comprises the second end 114. The pile module 100 further comprises a plurality of protrusions 140 on the outer side of the circumferential wall 120. In this example, the protrusions 140 are randomly arranged along essentially the entire length L of the tubular body 110. The protrusions 140 will increase the contact surface between the pile module 100 and the cement grout in the borehole.
[0054] Figure 2c shows an example where the pile module 100 comprises a plurality of openings 130 for the cement grout but they are primarily positioned on the lower half of the pile module 100, the half of the tubular body 110 that comprises the second end 114. The pile module further comprises a plurality of protrusions 140. In this example, the protrusions 140 are circumferential protrusions 140 extending around the outer side of the circumferential wall 120. The circumferential protrusions 140 are arranged at a predetermined distance from each other.Figure 2d shows an example where the pile module 100 comprises a plurality of openings 130 for the cement grout evenly distributed along the entire length L of the tubular body 110. The openings 130 are arranged in a predetermined pattern. The pile module 100 further comprises a plurality of circumferential protrusions 140 evenly distributed along the entire length L of the tubular body 110.
[0055] Figure 3 shows a cross-section of the pile module 100 disclosed in Figure 2d with three openings 130 separated by 120°. Thus, the three openings 130 are arranged on the same level on the tubular body 110. Figure 3 further shows that the openings 130 are chamfered so that they have a wider opening at the outer side of the circumferential wall 120. The angle between the sides of the wider opening is 60°.
[0056] Figure 4 shows a rock pile foundation system 500 according to an example of the present invention. In this example, the cement grout 20 has partly filled the borehole 10 in the bedrock 50. The rock pile foundation system 500 is configured as disclosed in Figure 1 but further comprises an injection arrangement 550 for leading the cement grout 20 to the pile module 100 and out to the borehole 10. The pile module 100 may be configured as in any of the previous figures and thus comprises a tubular body 110 with an open first end 112 and an open second end 114, a circumferential wall 120, and at least one opening 130.
[0057] The injection arrangement 550 comprises a hose section 552 and a pipe section 554. The pipe section 554 is first inserted into the pile 510 and is thus finally positioned inside the pile module 100. The hose section 552 extends through the pile elements 520 of the pile 510 The pipe section 554 comprises at least one aperture 556 at the end closest to the second end 114 of the pile module 100. The cement grout 20 will enter the inner space 124 of the tubular body 110 through the aperture 556. The injection arrangement 500 further comprise a stop plate 558 at the end closest to the second end 114 of the pile module 100, the stop plate 558 being configured to prevent the cement grout 20 to leave the pile module 100 via the second end 114. The injection arrangement 550 further comprises an inflatable manchette 560. The manchette 560 may be positioned inside the pile element 520 at the first end 112 of the tubular body 110 of the pile module 100. The manchette 560 will create a seal inside the pile element 520 and prevent cement grout 20 from exiting the pile module 100 via the first end 112. This way, the manchette 560 will ensure a high pressure in the pile module 100 and thereby ensure a good distribution of the cement grout 20 in the space between the tubular body 110 and the borehole wall 11. The inflatable manchette 560 can be expanded to fit tightly against the circumferential wall 120, providing additional stability.The hose section 552 runs through the manchette 560 and the pipe section 554 will start below the manchette 560 in order to deliver cement grout 20 to the tubular body 110. This arrangement will ensure that the cement grout 20 is distributed around the pile module 100, thereby enhancing the stability and load-bearing capacity of the foundation.
[0058] Figure 5 schematically illustrates details of a rock pile foundation system according to an example of the present invention. The system may be configured as disclosed in Figure 1 or 4. Figure 5 shows a connection between the pile element 520 and the pile module 100. In this example, the tubular body 110 of the pile module 100 comprises threads 116 at the first end 112. The pile element 520 also comprise threads 116 at the end connected to the pile module 100. The pile element 520 and the pile module 100 are connected by a coupling or sleeve 118 arranged around the pile element 520 and the pile module 100. The sleeve 118 comprises inner threads configured to engage with the threads 116 on the pile module 100 and the pile element 520.
[0059] Thes threads 116 enable a secure and adjustable fit, allowing for easy installation and removal of the pile module 100 from the pile element 520. The threads 116 ensure that the tubular body 110 remains firmly in place during operation. The threads 116 also enables the pile module 100 to be similarly connected to another pile module 100.
[0060] Figure 6 schematically illustrates details of a rock pile foundation system according to an example of the present invention. Figure 6 shows a connection between the pile element 520 and the pile module 100. In this example, the tubular body 110 is tapered at the first end 112. The pile element 520 is connected to the tubular body 110 of the pile module 100 by welding. The first end 112 of the tubular body 110 of the pile module 100 is arranged in abutment with the pile element 520 and they are welded together. It is to be understood that even if this figure shows the pile module 100 having a tapered or bevelled first end 112, the pile element 520 could additionally or alternatively have a tapered or bevelled end.
[0061] Figure 7 shows a method for installing a rock pile foundation system 500 as disclosed in Figure 1 or 4. This method can be implemented in various industrial applications where such sequential operations are required.
[0062] The method comprises drilling slOO a borehole 10 through the ground and into the bedrock 50 while simultaneously advancing the at least one pile 510 and pile module 100 through the borehole 10 until the pile module 100 has reached a desired position in the bedrock 50. This step involves creating a hole or cavity through the soil 40 and the bedrock 50using a drilling arrangement. The method further comprises pumping sl20 cement grout 20 through the rock pile foundation system 500 with a pressure so that the cement grout 20 is discharged through the at least one opening 130 in the pile module 100 to the surrounding borehole 10 in the bedrock 50.
[0063] The step of drilling slOO the borehole 10 may be performed using a top hammer or a down the hole (DTH) hammer. It is to be understood that this step also may involve connecting further pile elements 520 as the borehole 10 gets deeper and deeper. The step of drilling slOO the borehole 10 may further comprise to first connect a drill element 400 to the second end 112 of the pile module 100. The drill element 400 may be a coupling element for connection to a drill bit or it may be a drill bit. Furthermore, the step of drilling slOO the borehole 10 may also comprise removing the drill element 400 or at least a part of the drill element 400 and / or removing a drill string when the pile module 100 has reached its desired position in the bedrock 50.
[0064] When the borehole 10 is ready and the rock pile foundation system 500 is positioned at the bottom of the borehole 10, the pumping sl20 of cement grout 20 is initiated. The step of pumping sl20 cement grout 20 through the pile system 500 may first involve mixing the cement grout 20 so that the cement grout 20 has the correct characteristics depending on the intended use or the characteristics of the bedrock 50. Furthermore, the pumping sl20 is performed with a pressure higher than the hydrostatic pressure.
[0065] The step of pumping sl20 the cement grout 20 may also comprise inserting an injection arrangement 550 into the pile system 500 for injecting the cement grout 20. The step of inserting the injection arrangement 550 may comprise arranging an inflatable manchette 560 at the first end 112 of the pile module 100, to prevent cement grout 20 from leaving the pile module 100 through the first end 112. The manchette 560 is positioned inside the pile element 520 connected to the pile module 100.
[0066] It should be noted that the examples shown in the drawings are for illustrating purposes only, and many other alternatives may be contemplated within the scope of the present invention.
Claims
CLAIMS1. A pile module (100) for a rock pile foundation system (500), the pile module (100) being configured to transfer compressive and tensile loads and comprising a tubular body (110) with an open first end (112) and an open second end (114), wherein the pile module (100) is connectable to a pile element (520) at the first end (112), and is configured to transfer compressive loads at the second end (114), wherein the tubular body (110) comprises a circumferential wall (120) forming an inner space (124), wherein the circumferential wall (120) comprises at least one opening (130) for discharging a cement grout (20) from the inner space (124) to a borehole (10) in the bedrock and thereby securing the pile module (100).
2. The pile module (100) according to claim 1, wherein the tubular body (110) comprises a plurality of openings (130) distributed along the circumferential wall (120).
3. The pile module (100) according to claim 1 or 2, wherein the circumferential wall (120) comprises a machined surface (122) to increase the shaft resistance between the pile module (100) and the cement grout (20).
4. The pile module (100) according to claim 1 or 2, further comprising at least one protrusion (140) on an outer side of the circumferential wall (120).
5. The pile module (100) according to claim 4, wherein the at least one protrusion (140) is a circumferential protrusion.
6. The pile module (100) according to claim 4 or 5, wherein the at least one protrusion (140) protrudes 0,1-1 cm from the circumferential wall (120).
7. The pile module (100) according to any one of the preceding claims, wherein the pile module (100) is designed to fit a micro-pile system.
8. The pile module (100) according to any one of the preceding claims, wherein the pile module (100) has a length (L) extending between the first end (112) and the second end (114), wherein the length (L) is within the range of 0,5-6 meters, preferably between 1-2 meters.
9. The pile module (100) according to any one of the preceding claims, wherein the first end (112) of the tubular body (110) comprises threads (116) for connection with the pile element (520).
10. The pile module (100) according to any one of claims 1-8, wherein the first end (112) of the tubular body (110) is tapered for welded connection with the pile element (520).
11. A rock pile foundation system (500) comprising:at least one pile (510) including at least one pile element (520);andat least one pile module (100) according to any one of the preceding claims, wherein the first end (112) of the at least one pile module (100) is connected to the at least one pile element (520).
12. The system (500) according to claim 11, wherein the system (500) is a micro-pile system.
13. A method for installing a rock pile foundation system (500) according to claim 11 or 12 in a bedrock (50), the method comprising the steps of:drilling (slOO) a borehole (10) through the ground into the bedrock (50) while simultaneously advancing the at least one pile (510) and pile module (100) through the borehole (10) until the pile module (100) has reached a desired position in the bedrock (50); andpumping (sl20) cement grout (20) through the rock pile foundation system (500) with a pressure so that the cement grout (20) is discharged through the at least one opening (130) in the pile module (100) to the surrounding borehole (10) in the bedrock (50).
14. The method according to claim 13, wherein the step of pumping (sl20) the cement grout (20) further comprises inserting an injection arrangement (550) into the rock pile foundation system (500) for injecting the cement grout (20).
15. The method according to claim 14, wherein inserting the injection arrangement (550) comprises arranging an inflatable manchette (560) at the first end (112) of the pile module (100), to prevent cement grout (20) from leaving the pile module (100) through the first end (112).