EP1382750A1 - Ground improvement - Google Patents
Ground improvement Download PDFInfo
- Publication number
- EP1382750A1 EP1382750A1 EP03254512A EP03254512A EP1382750A1 EP 1382750 A1 EP1382750 A1 EP 1382750A1 EP 03254512 A EP03254512 A EP 03254512A EP 03254512 A EP03254512 A EP 03254512A EP 1382750 A1 EP1382750 A1 EP 1382750A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- ground
- lance
- additional material
- amelioration
- lance member
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
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Classifications
-
- E—FIXED CONSTRUCTIONS
- E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
- E01C—CONSTRUCTION OF, OR SURFACES FOR, ROADS, SPORTS GROUNDS, OR THE LIKE; MACHINES OR AUXILIARY TOOLS FOR CONSTRUCTION OR REPAIR
- E01C7/00—Coherent pavings made in situ
- E01C7/36—Coherent pavings made in situ by subjecting soil to stabilisation
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- E—FIXED CONSTRUCTIONS
- E01—CONSTRUCTION OF ROADS, RAILWAYS, OR BRIDGES
- E01C—CONSTRUCTION OF, OR SURFACES FOR, ROADS, SPORTS GROUNDS, OR THE LIKE; MACHINES OR AUXILIARY TOOLS FOR CONSTRUCTION OR REPAIR
- E01C3/00—Foundations for pavings
- E01C3/04—Foundations produced by soil stabilisation
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D3/00—Improving or preserving soil or rock, e.g. preserving permafrost soil
- E02D3/02—Improving by compacting
- E02D3/046—Improving by compacting by tamping or vibrating, e.g. with auxiliary watering of the soil
- E02D3/054—Improving by compacting by tamping or vibrating, e.g. with auxiliary watering of the soil involving penetration of the soil, e.g. vibroflotation
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- E—FIXED CONSTRUCTIONS
- E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
- E02D—FOUNDATIONS; EXCAVATIONS; EMBANKMENTS; UNDERGROUND OR UNDERWATER STRUCTURES
- E02D3/00—Improving or preserving soil or rock, e.g. preserving permafrost soil
- E02D3/02—Improving by compacting
- E02D3/08—Improving by compacting by inserting stones or lost bodies, e.g. compaction piles
Definitions
- the present invention relates to ground improvement, particularly, but not exclusively, prior to building.
- the present invention provides a method of ground improvement, in which an array of locations is locally improved by vibrating a lance member into the ground repeatedly at each location, withdrawing the lance member to leave an elongate cavity, and introducing additional material into the cavities so formed, prior to the reintroduction of the lance member to compact the additional material and the surrounding ground, and in which a cap formation is provided at each improved location by forming a depression at the surface and filling the depression with material which includes ground amelioration material, and in which a surface layer of the ground is disturbed to mix the ground with a ground amelioration material to form a pavement which interconnects cap formations at the improved locations.
- ground amelioration material refers to a material which consists of, or includes, a binder capable of increasing cohesion in material such as soil.
- the binder may be a settable material such as a cementitious material.
- the binder is cement.
- bitumen may be used as a binder.
- Ground amelioration material may also incorporate additional granular material such as pulverised fuel ash, and hydrophilic material such as quick lime, to assist in controlling pore pressure of the material and of the surrounding ground.
- the term “ameliorated soil” is used to refer to soil, preferably derived locally, into which ground amelioration material has been mixed.
- the additional material introduced into the cavities may be particulate and may comprise stone, gravel or another aggregate material.
- the additional material preferably includes ground amelioration material.
- the additional material may comprise soil mixed with ground amelioration material.
- the lance member may be repeatedly introduced at the same position, until heave is detected in the ground around that position.
- the surface depressions are preferably formed by impact from a dropped weight.
- the dropped weight may be a tapered member having a relatively narrow nose, forming a point of first contact with the ground, and widening from the nose.
- the dropped weight may widen to a width greater than the lance member, whereby to flare out the top of the material compacted by the lance member.
- the drawings illustrate a method of preparing ground in accordance with the present invention.
- the method is primarily intended for bad ground which has low natural load bearing capacity.
- Bad ground may, for example, include peat.
- peat It will be understood by the skilled reader that in many practical situations, no clear delineation can be made between good ground and bad ground, there being a continuous spectrum of ground quality. Indeed, the term "marginal ground” is sometimes used to refer to ground which is between good and bad ground. Consequently, the choice of technique to be used will be made in accordance with the quality of the ground in its natural state, the nature of the load imposed by the building to be constructed and other factors.
- Fig. 1 shows a lance member 14, for use in the method of the invention.
- the lance is used to provide local improvement of the ground at each location of an array of locations across the area being improved.
- the lance 14 is driven into the ground by vibration, to form an elongate cavity 16 (Fig. 2) in the ground 17.
- the lance 14 is then withdrawn and the cavity 16 is filled with additional material 19.
- the additional material may be particulate in nature, such as stone, gravel or another aggregate.
- the additional material may be ground amelioration material, or ameliorated soil.
- quick lime is included in the additional material.
- the presence of quick lime which is highly hydrophilic, causes ground water to be drawn strongly from the surrounding ground 17, causing a significant reduction in local pore pressure. Consequently, the addition of quick lime is particularly preferred in locations at which excessive pore pressure is expected to be a problem. The reduction in pore pressure helps overcome any tendency of fine-grained soils to liquefy during the procedure.
- the lance 14 has an inverted frusto-conical shape.
- the lance 14 may have a diameter of about 300mm at its upper end and about 150mm at its lower end 14A, with a length of approximately 3m.
- the lance 14 is attached to extend down, substantially vertically, from a vibrator arrangement 18 which applies vertical oscillation to the lance 14 during use.
- the vertical oscillation may have an amplitude of about 25mm and a frequency of 1500 cycles per minute, with a rated impact per blow in excess of 40 tonnes.
- the cone angle of the lance 14 may be low, such as between 2° and 5°.
- the lance 14 will be driven into the ground substantially Without impact in a horizontal direction between the surface of the lance 14 and the sides of the cavity 16. That is, the main impact with the ground will be at the bottom of the cavity 16 as the lance 14 forces itself deeper into the ground.
- the lance 14 can be driven, by vibration, to any chosen depth without causing pore pressure problems, whereas the depth of compaction created by impact must be limited because of the force of impact and the resultant shock waves of pore pressure.
- the lance 14 is withdrawn. Additional material 19 is then introduced into the cavity.
- the additional material may be particulate, but preferably includes ground amelioration material or is ameliorated soil. This introduction of additional material results in the intermediate situation illustrated in Fig. 2.
- the lance 14 is then reintroduced into the ground, at the same location, and vibrated down to cause compaction of the additional material. This may result in bulging of the cavity 16, as shown at 38 (Fig. 3), arising from the inability of the surrounding ground 17 to contain the compaction forces created by the lance 14. The degree of bulging which occurs will depend on the size of downward compacting forces created by the vibration of the lance 14, and the natural capacity of the surrounding ground 34 to provide lateral containment of the additional material.
- the lance 14 is repeatedly vibrated in, removed and reintroduced after additional material has been introduced, until the cavity 16 is full of material which has been adequately compacted, with resultant bulging of the cavity.
- Compaction of the additional material in the cavity 16 is preferably continued until the ground 17 is seen to heave upwardly (indicated at 39) around the position of the cavity 16. This heave indicates that no further additional material can be accommodated, and no further compaction is possible.
- the next stage of the method is to provide a cap formation (to be described) at each of the locations which has been improved as described above.
- the cap formation is provided by forming a depression at the surface, and filling the depression with material which includes ground amelioration material or ameliorated soil.
- the depression is preferably formed by impact from a dropped weight.
- a preferred device for use as a drop weight is shown in Fig. 4.
- the device 30 has a relatively narrow nose 32 which provides, in use, the point of first contact with the ground, when the device 10 is dropped.
- the device tapers down to the the nose 32, over a portion 34.
- a clevis arrangement 36 allows the device 30 to hang from a cable 37 to allow the device 30 to be raised by a crane, and then dropped to the ground.
- the weight of the device 30 is preferably at least 2,500 kg and preferably considerably more, such as 7,500 kg or 8,000 kg.
- the portion 34 preferably widens at an angle of 14° or greater, i.e. greater than the so called Morse angle of 14°. (The angle is measured between the central (vertical) axis of the device 30, and the tapering outer surface of the portion 34).
- the Morse angle of 14° is generally considered as the minimum angle required, to prevent the device 30 sticking in the ground, after being dropped.
- An angle between 14° and 20°, preferably about 17° may be chosen.
- Fig. 5 schematically shows the device 30, prior to it being dropped onto a location 40 which has already been improved by the first part of the method, in the manner described above. It is to be noted, and is preferred, that the device 30 is considerably wider than the lance 14, and is thus wider than the mouth 42 of the cavity 16.
- the device 30 is then dropped to embed itself in the material of the cavity 16 and is then removed.
- the result is shown in Fig. 6.
- the compacted material previously introduced into the cavity 16 has been flared out at 44.
- the depression 46 is then filled with ground amelioration material to ground level, indicated at 48.
- the device 30 is dropped again and then removed, to form a further depression 30A. This results in additional outward and downward compaction of the surrounding ground 26.
- the additional material introduced prior to the drop is forced out into the surrounding ground forming a body of ameliorated soil around the depression 30A.
- the process is then repeated again, by filling the depression with additional material, dropping the device 30 to form a depression (not shown) and then filling the resulting depression again. It is preferred that additional material is introduced after each drop, but in some circumstances it may be appropriate to drop the device 30 more than once, before further additional material is introduced.
- Fig. 7 schematically shows three locations which have been treated in this manner, by means of the lance and subsequently by means of the device 30.
- the improved locations now form an array of pillars 49 of improved ground, separated by regions 50 which may still be in their original condition, but are likely to have been improved to some degree, as a result of the compaction, bursting etc. This completes the second part of the method.
- a surface layer 52 of the ground 17 (the depth of which is indicated by a broken line 54 in Fig. 7) is disturbed and mixed with ground amelioration material. This may be achieved by using a rotavator device, introducing the ground amelioration material either before or after rotavation. Alternatively, the material of the surface layer 52 may be removed for mixing and reintroduction. In a further alternative, the surface layer 52 may be disturbed to mix in ground amelioration material prior to the use of the lance 14. It is preferred that the surface layer 52 is formed without removing soil from the site, in order to speed up the process and minimise external environmental impact.
- the surface layer 52 is preferably formed before cementitious binder introduced into the depressions 46 (and in the cavities 16, if they were filled with ground amelioration material including a settable binder) has set, so that a unitary structure is formed as shown in Fig. 8.
- Fig. 8 shows a series of neighbouring locations 40, interconnected by the surface layer 52.
- the surface layer 52 has been formed prior to the cementitious binder setting at the locations 40 and consequently, once the material sets, a single unitary structure is formed, consisting of supporting pillars 56 and a surface pavement 52.
- the pillars 56 will be arrayed in two dimensions across the ground and thus, the pavement 52 will cover the entire area being treated, with support at each pillar 56.
- the result is a structure similar to a vaulted roof construction and with similar strength and load bearing characteristics arising from the unitary nature of the complete structure.
- the similarity with a vaulted roof is enhanced by the flaring achieved at the top of the pillars 56, by the use of the weight 30.
- the load bearing capacity will be further increased by the presence of the ground between the pillars 56, which will provide lateral stability for the pillars 56, and support for the pavement 52.
- the load bearing capacity of the pavement 52 is thus expected to be greater than that of an unsupported pavement, by virtue of the support provided by the ground beneath, and by the pillars 56.
- the method may be used to prepare ground for large commercial buildings such as retail sheds. Retail sheds may require relatively low loading on the ground over relatively large areas, with high loads around the edge of the building. Consequently, the unitary pillar and pavement structure described above can be used for providing adequate ground over the area of the building. It may be desirable to provide conventional piling systems at the edges of the building, to improve support for the building itself.
- Additional steps can be incorporated in the method, to further improve the performance of the ground.
- a large weight in the form of a plate, may be dropped to provide additional compaction of the ground, prior to the formation of the surface pavement layer.
- the weight may be a device of the type described in International patent application no. WO 99/09261, particularly in relation to Figs. 9, 10 or 11 of that application.
- the weight is repeatedly dropped as it is moved across the ground, so that substantially the whole of the area has been subjected to impact from the weight, thus further consolidating the ground prior to the formation of the pavement layer.
- a final step of passing a roller over the site may be used, to further improve levelling and compacting.
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- Engineering & Computer Science (AREA)
- Structural Engineering (AREA)
- Life Sciences & Earth Sciences (AREA)
- Civil Engineering (AREA)
- General Life Sciences & Earth Sciences (AREA)
- General Engineering & Computer Science (AREA)
- Environmental & Geological Engineering (AREA)
- Soil Sciences (AREA)
- Architecture (AREA)
- Mining & Mineral Resources (AREA)
- Paleontology (AREA)
- Agronomy & Crop Science (AREA)
- Consolidation Of Soil By Introduction Of Solidifying Substances Into Soil (AREA)
- Superconductors And Manufacturing Methods Therefor (AREA)
- Soil Working Implements (AREA)
- Investigation Of Foundation Soil And Reinforcement Of Foundation Soil By Compacting Or Drainage (AREA)
- Road Repair (AREA)
- Soil Conditioners And Soil-Stabilizing Materials (AREA)
- Road Paving Structures (AREA)
Abstract
Description
- The present invention relates to ground improvement, particularly, but not exclusively, prior to building.
- The present invention provides a method of ground improvement, in which an array of locations is locally improved by vibrating a lance member into the ground repeatedly at each location, withdrawing the lance member to leave an elongate cavity, and introducing additional material into the cavities so formed, prior to the reintroduction of the lance member to compact the additional material and the surrounding ground,
and in which a cap formation is provided at each improved location by forming a depression at the surface and filling the depression with material which includes ground amelioration material,
and in which a surface layer of the ground is disturbed to mix the ground with a ground amelioration material to form a pavement which interconnects cap formations at the improved locations. - In this specification, the term "ground amelioration material" refers to a material which consists of, or includes, a binder capable of increasing cohesion in material such as soil. The binder may be a settable material such as a cementitious material. Preferably, the binder is cement. Alternatively, bitumen may be used as a binder. Ground amelioration material may also incorporate additional granular material such as pulverised fuel ash, and hydrophilic material such as quick lime, to assist in controlling pore pressure of the material and of the surrounding ground. The term "ameliorated soil" is used to refer to soil, preferably derived locally, into which ground amelioration material has been mixed.
- The additional material introduced into the cavities may be particulate and may comprise stone, gravel or another aggregate material. The additional material preferably includes ground amelioration material. The additional material may comprise soil mixed with ground amelioration material.
- The lance member may be repeatedly introduced at the same position, until heave is detected in the ground around that position.
- The surface depressions are preferably formed by impact from a dropped weight. The dropped weight may be a tapered member having a relatively narrow nose, forming a point of first contact with the ground, and widening from the nose. The dropped weight may widen to a width greater than the lance member, whereby to flare out the top of the material compacted by the lance member.
- An example of the present invention will now be described in more detail, by way of example only, and with reference to the accompanying drawings, in which:
- Fig. 1 is an elevation of a lance member for use in accordance with the method of the invention;
- Figs. 2 and 3 illustrate the sequence of steps of a first part of the method;
- Fig. 4 is an elevation of a weight for use in a second part of the method;
- Figs. 5, 6 and 7 show the sequence of steps of the second part of the method; and
- Fig. 8 illustrates the third part of the method and the final condition of the ground.
-
- The drawings illustrate a method of preparing ground in accordance with the present invention. The method is primarily intended for bad ground which has low natural load bearing capacity. Bad ground may, for example, include peat. It will be understood by the skilled reader that in many practical situations, no clear delineation can be made between good ground and bad ground, there being a continuous spectrum of ground quality. Indeed, the term "marginal ground" is sometimes used to refer to ground which is between good and bad ground. Consequently, the choice of technique to be used will be made in accordance with the quality of the ground in its natural state, the nature of the load imposed by the building to be constructed and other factors.
- Fig. 1 shows a
lance member 14, for use in the method of the invention. The lance is used to provide local improvement of the ground at each location of an array of locations across the area being improved. At each location, thelance 14 is driven into the ground by vibration, to form an elongate cavity 16 (Fig. 2) in theground 17. Thelance 14 is then withdrawn and thecavity 16 is filled withadditional material 19. The additional material may be particulate in nature, such as stone, gravel or another aggregate. Alternatively, the additional material may be ground amelioration material, or ameliorated soil. - Preferably quick lime is included in the additional material. The presence of quick lime, which is highly hydrophilic, causes ground water to be drawn strongly from the surrounding
ground 17, causing a significant reduction in local pore pressure. Consequently, the addition of quick lime is particularly preferred in locations at which excessive pore pressure is expected to be a problem. The reduction in pore pressure helps overcome any tendency of fine-grained soils to liquefy during the procedure. - The
lance 14 has an inverted frusto-conical shape. In one example, thelance 14 may have a diameter of about 300mm at its upper end and about 150mm at itslower end 14A, with a length of approximately 3m. Thelance 14 is attached to extend down, substantially vertically, from avibrator arrangement 18 which applies vertical oscillation to thelance 14 during use. For example, the vertical oscillation may have an amplitude of about 25mm and a frequency of 1500 cycles per minute, with a rated impact per blow in excess of 40 tonnes. The cone angle of thelance 14 may be low, such as between 2° and 5°. - In consequence of the shape of the
lance 14 and the use of vertical vibration, thelance 14 will be driven into the ground substantially Without impact in a horizontal direction between the surface of thelance 14 and the sides of thecavity 16. That is, the main impact with the ground will be at the bottom of thecavity 16 as thelance 14 forces itself deeper into the ground. - Contact with the sides of the
cavity 16 will consist primarily of a pressing action, causing ground material to be pressed gently sideways to form thecavity 16, without harsh impacts. Avoiding impacts in this manner results in the technique minimising shocks which can result in increased pore pressure in water-laden ground and, in extreme cases, can cause liquefaction of ground. Depressions formed by impact can cause significant and sudden increases in pore pressure, with consequential disturbance to the ground at some considerable distance from the point of working. - The
lance 14 can be driven, by vibration, to any chosen depth without causing pore pressure problems, whereas the depth of compaction created by impact must be limited because of the force of impact and the resultant shock waves of pore pressure. - Once the
cavity 16 has been formed, thelance 14 is withdrawn.Additional material 19 is then introduced into the cavity. As has been described, the additional material may be particulate, but preferably includes ground amelioration material or is ameliorated soil. This introduction of additional material results in the intermediate situation illustrated in Fig. 2. - The
lance 14 is then reintroduced into the ground, at the same location, and vibrated down to cause compaction of the additional material. This may result in bulging of thecavity 16, as shown at 38 (Fig. 3), arising from the inability of the surroundingground 17 to contain the compaction forces created by thelance 14. The degree of bulging which occurs will depend on the size of downward compacting forces created by the vibration of thelance 14, and the natural capacity of the surroundingground 34 to provide lateral containment of the additional material. Thelance 14 is repeatedly vibrated in, removed and reintroduced after additional material has been introduced, until thecavity 16 is full of material which has been adequately compacted, with resultant bulging of the cavity. - Compaction of the additional material in the
cavity 16 is preferably continued until theground 17 is seen to heave upwardly (indicated at 39) around the position of thecavity 16. This heave indicates that no further additional material can be accommodated, and no further compaction is possible. - The next stage of the method is to provide a cap formation (to be described) at each of the locations which has been improved as described above. The cap formation is provided by forming a depression at the surface, and filling the depression with material which includes ground amelioration material or ameliorated soil. The depression is preferably formed by impact from a dropped weight. A preferred device for use as a drop weight is shown in Fig. 4. The
device 30 has a relativelynarrow nose 32 which provides, in use, the point of first contact with the ground, when the device 10 is dropped. The device tapers down to the thenose 32, over aportion 34. Aclevis arrangement 36 allows thedevice 30 to hang from acable 37 to allow thedevice 30 to be raised by a crane, and then dropped to the ground. The weight of thedevice 30 is preferably at least 2,500 kg and preferably considerably more, such as 7,500 kg or 8,000 kg. Theportion 34 preferably widens at an angle of 14° or greater, i.e. greater than the so called Morse angle of 14°. (The angle is measured between the central (vertical) axis of thedevice 30, and the tapering outer surface of the portion 34). The Morse angle of 14° is generally considered as the minimum angle required, to prevent thedevice 30 sticking in the ground, after being dropped. An angle between 14° and 20°, preferably about 17° may be chosen. - Fig. 5 schematically shows the
device 30, prior to it being dropped onto alocation 40 which has already been improved by the first part of the method, in the manner described above. It is to be noted, and is preferred, that thedevice 30 is considerably wider than thelance 14, and is thus wider than themouth 42 of thecavity 16. - The
device 30 is then dropped to embed itself in the material of thecavity 16 and is then removed. The result is shown in Fig. 6. The compacted material previously introduced into thecavity 16 has been flared out at 44. Thedepression 46 is then filled with ground amelioration material to ground level, indicated at 48. - After the additional material has been introduced into the
depression 46, thedevice 30 is dropped again and then removed, to form a further depression 30A. This results in additional outward and downward compaction of the surrounding ground 26. In addition, the additional material introduced prior to the drop is forced out into the surrounding ground forming a body of ameliorated soil around the depression 30A. - The process is then repeated again, by filling the depression with additional material, dropping the
device 30 to form a depression (not shown) and then filling the resulting depression again. It is preferred that additional material is introduced after each drop, but in some circumstances it may be appropriate to drop thedevice 30 more than once, before further additional material is introduced. - Fig. 7 schematically shows three locations which have been treated in this manner, by means of the lance and subsequently by means of the
device 30. The improved locations now form an array ofpillars 49 of improved ground, separated byregions 50 which may still be in their original condition, but are likely to have been improved to some degree, as a result of the compaction, bursting etc. This completes the second part of the method. - Further steps are now taken to interconnect the structures which have been formed in the manner described above, across the whole area to be improved. A
surface layer 52 of the ground 17 (the depth of which is indicated by a broken line 54 in Fig. 7) is disturbed and mixed with ground amelioration material. This may be achieved by using a rotavator device, introducing the ground amelioration material either before or after rotavation. Alternatively, the material of thesurface layer 52 may be removed for mixing and reintroduction. In a further alternative, thesurface layer 52 may be disturbed to mix in ground amelioration material prior to the use of thelance 14. It is preferred that thesurface layer 52 is formed without removing soil from the site, in order to speed up the process and minimise external environmental impact. - The
surface layer 52 is preferably formed before cementitious binder introduced into the depressions 46 (and in thecavities 16, if they were filled with ground amelioration material including a settable binder) has set, so that a unitary structure is formed as shown in Fig. 8. Fig. 8 shows a series ofneighbouring locations 40, interconnected by thesurface layer 52. Thesurface layer 52 has been formed prior to the cementitious binder setting at thelocations 40 and consequently, once the material sets, a single unitary structure is formed, consisting of supportingpillars 56 and asurface pavement 52. Naturally, thepillars 56 will be arrayed in two dimensions across the ground and thus, thepavement 52 will cover the entire area being treated, with support at eachpillar 56. The result is a structure similar to a vaulted roof construction and with similar strength and load bearing characteristics arising from the unitary nature of the complete structure. The similarity with a vaulted roof is enhanced by the flaring achieved at the top of thepillars 56, by the use of theweight 30. However, it is expected that the load bearing capacity will be further increased by the presence of the ground between thepillars 56, which will provide lateral stability for thepillars 56, and support for thepavement 52. The load bearing capacity of thepavement 52 is thus expected to be greater than that of an unsupported pavement, by virtue of the support provided by the ground beneath, and by thepillars 56. - There has thus been described a method which can readily be used for good or bad ground. The method may be used to prepare ground for large commercial buildings such as retail sheds. Retail sheds may require relatively low loading on the ground over relatively large areas, with high loads around the edge of the building. Consequently, the unitary pillar and pavement structure described above can be used for providing adequate ground over the area of the building. It may be desirable to provide conventional piling systems at the edges of the building, to improve support for the building itself.
- Various modifications and alterations can be made to the steps described above, without departing from the scope of the present invention. In particular, the number and layout of locations to be treated by the lance can be varied according to the original quality of the ground and the required final quality. The relative dimensions of the pavement and pillars may also be changed.
- Additional steps can be incorporated in the method, to further improve the performance of the ground. For example, a large weight, in the form of a plate, may be dropped to provide additional compaction of the ground, prior to the formation of the surface pavement layer. The weight may be a device of the type described in International patent application no. WO 99/09261, particularly in relation to Figs. 9, 10 or 11 of that application. The weight is repeatedly dropped as it is moved across the ground, so that substantially the whole of the area has been subjected to impact from the weight, thus further consolidating the ground prior to the formation of the pavement layer. A final step of passing a roller over the site may be used, to further improve levelling and compacting.
- Whilst endeavouring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon.
Claims (9)
- A method of ground improvement, in which an array of locations is locally improved by vibrating a lance member into the ground repeatedly at each location, withdrawing the lance member to leave an elongate cavity, and introducing additional material into the cavities so formed, prior to the reintroduction of the lance member to compact the additional material and the surrounding ground,
and in which a cap formation is provided at each improved location by forming a depression at the surface and filling the depression with material which includes ground amelioration material,
and in which a surface layer of the ground is disturbed to mix the ground with a ground amelioration material to form a pavement which interconnects cap formations at the improved locations. - A method according to claim 1, wherein the additional material introduced into the cavities is particulate.
- A method according to claim 2, wherein the additional material comprises stone, gravel or another aggregate material.
- A method according to any preceding claim, wherein the additional material includes ground amelioration material.
- A method according to any preceding claim, wherein the additional material comprises soil mixed with ground amelioration material.
- A method according to any preceding claim, wherein the lance member is repeatedly introduced at the same position, until heave is detected in the ground around that position.
- A method according to any preceding claim, wherein the surface depressions are formed by impact from a dropped weight.
- A method according to claim 7, wherein the dropped weight is a tapered member having a relatively narrow nose, forming a point of first contact with the ground, and widening from the nose.
- A method according to claim 8, wherein the dropped weight widens to a width greater than the lance member, whereby to flare out the top of the material compacted by the lance member.
Applications Claiming Priority (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB0216701A GB0216701D0 (en) | 2002-07-18 | 2002-07-18 | Preparation of ground prior to building |
GB0216701 | 2002-07-18 | ||
GB0225943 | 2002-11-07 | ||
GB0225943A GB0225943D0 (en) | 2002-07-18 | 2002-11-07 | Preparation of ground prior to building |
Publications (2)
Publication Number | Publication Date |
---|---|
EP1382750A1 true EP1382750A1 (en) | 2004-01-21 |
EP1382750B1 EP1382750B1 (en) | 2009-08-19 |
Family
ID=27767110
Family Applications (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP03254512A Expired - Lifetime EP1382750B1 (en) | 2002-07-18 | 2003-07-18 | Ground improvement |
EP03254513A Expired - Lifetime EP1382751B1 (en) | 2002-07-18 | 2003-07-18 | Ground improvement |
Family Applications After (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP03254513A Expired - Lifetime EP1382751B1 (en) | 2002-07-18 | 2003-07-18 | Ground improvement |
Country Status (5)
Country | Link |
---|---|
EP (2) | EP1382750B1 (en) |
AT (2) | ATE440183T1 (en) |
DE (2) | DE60328853D1 (en) |
ES (2) | ES2331239T3 (en) |
GB (2) | GB2391035B (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1498550A2 (en) * | 2003-07-18 | 2005-01-19 | Roxbury Limited | Ground improvement |
WO2011001297A1 (en) * | 2009-06-30 | 2011-01-06 | Russet Trading & Investment 24 (Pty) Ltd | A method for constructing a column |
WO2017147424A1 (en) * | 2016-02-24 | 2017-08-31 | Ingios Geotechnics, Inc. | Systems and methods to provide pressed and aggregate filled concavities for improving ground stiffness and uniformity |
GB2595274A (en) * | 2020-05-20 | 2021-11-24 | Subsea 7 Norway As | Modifying seabed contours |
Families Citing this family (7)
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EP2386000B1 (en) * | 2009-01-09 | 2014-11-26 | Geopier Foundation Company, Inc. | Construction modulus testing apparatus and method |
DE102010022661A1 (en) * | 2010-06-04 | 2011-12-08 | vgs Ingenieure Dr. Köhler & Kirschstein GmbH | Methods for soil compaction of sands and gravels, involves generating vertical vibration movements of compression tool by vibration device which is fitted on upper end of compression tool |
CN102409588B (en) * | 2011-11-25 | 2013-06-12 | 中铁十二局集团第三工程有限公司 | Movable grouting workshop |
CN102535291A (en) * | 2012-02-02 | 2012-07-04 | 石家庄铁道大学 | Soft-soil foundation treatment method for expressway engineering |
CN105970995A (en) * | 2016-05-25 | 2016-09-28 | 宁波市建设集团股份有限公司 | Bearing platform mold |
CN109183542A (en) * | 2018-07-26 | 2019-01-11 | 武汉大学 | Run highway soft soil roadbed bumping at bridge-head lower clapboard processing method |
CN109355990B (en) * | 2018-11-29 | 2023-09-19 | 中国电建集团成都勘测设计研究院有限公司 | Ultra-fine sand roadbed structure for hydraulic filling in low-lying marsh areas |
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US5249892A (en) * | 1991-03-20 | 1993-10-05 | Fox Nathaniel S | Short aggregate piers and method and apparatus for producing same |
GB2286613A (en) * | 1994-02-18 | 1995-08-23 | Roxbury Ltd | Ground improvement |
EP0921234A1 (en) * | 1997-12-04 | 1999-06-09 | Ballast Nedam Funderingstechnieken B.V. | Method and device for arranging a pile in a ground |
GB2366819A (en) * | 1997-08-20 | 2002-03-20 | Roxbury Ltd | Monitoring the degree of compaction during ground treatment |
Family Cites Families (2)
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ES2279991T3 (en) * | 1997-08-20 | 2007-09-01 | Roxbury Limited | LAND TREATMENT. |
GB2365891B (en) * | 2000-07-07 | 2004-05-26 | Roxbury Ltd | Ground preparation |
-
2003
- 2003-07-18 AT AT03254513T patent/ATE440183T1/en not_active IP Right Cessation
- 2003-07-18 DE DE60328853T patent/DE60328853D1/en not_active Expired - Fee Related
- 2003-07-18 GB GB0316860A patent/GB2391035B/en not_active Expired - Fee Related
- 2003-07-18 DE DE60328854T patent/DE60328854D1/en not_active Expired - Fee Related
- 2003-07-18 EP EP03254512A patent/EP1382750B1/en not_active Expired - Lifetime
- 2003-07-18 ES ES03254513T patent/ES2331239T3/en not_active Expired - Lifetime
- 2003-07-18 ES ES03254512T patent/ES2331238T3/en not_active Expired - Lifetime
- 2003-07-18 EP EP03254513A patent/EP1382751B1/en not_active Expired - Lifetime
- 2003-07-18 AT AT03254512T patent/ATE440182T1/en not_active IP Right Cessation
- 2003-07-18 GB GB0316861A patent/GB2391036B/en not_active Expired - Fee Related
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
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US5249892A (en) * | 1991-03-20 | 1993-10-05 | Fox Nathaniel S | Short aggregate piers and method and apparatus for producing same |
GB2286613A (en) * | 1994-02-18 | 1995-08-23 | Roxbury Ltd | Ground improvement |
GB2366819A (en) * | 1997-08-20 | 2002-03-20 | Roxbury Ltd | Monitoring the degree of compaction during ground treatment |
EP0921234A1 (en) * | 1997-12-04 | 1999-06-09 | Ballast Nedam Funderingstechnieken B.V. | Method and device for arranging a pile in a ground |
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1498550A2 (en) * | 2003-07-18 | 2005-01-19 | Roxbury Limited | Ground improvement |
EP1498550A3 (en) * | 2003-07-18 | 2006-01-18 | Roxbury Limited | Ground improvement |
WO2011001297A1 (en) * | 2009-06-30 | 2011-01-06 | Russet Trading & Investment 24 (Pty) Ltd | A method for constructing a column |
WO2017147424A1 (en) * | 2016-02-24 | 2017-08-31 | Ingios Geotechnics, Inc. | Systems and methods to provide pressed and aggregate filled concavities for improving ground stiffness and uniformity |
US10196793B2 (en) | 2016-02-24 | 2019-02-05 | Ingios Geotechnics, Inc. | Systems and methods to provide pressed and aggregate filled concavities for improving ground stiffness and uniformity |
US11085160B2 (en) | 2016-02-24 | 2021-08-10 | Ingios Geotechnics, Inc. | Method to provide pressed and aggregate filled concavities for improving ground stiffness and uniformity |
GB2595274A (en) * | 2020-05-20 | 2021-11-24 | Subsea 7 Norway As | Modifying seabed contours |
GB2595274B (en) * | 2020-05-20 | 2023-07-05 | Subsea 7 Norway As | Modifying seabed contours |
Also Published As
Publication number | Publication date |
---|---|
EP1382751A1 (en) | 2004-01-21 |
GB2391035B (en) | 2005-05-04 |
ES2331238T3 (en) | 2009-12-28 |
GB0316861D0 (en) | 2003-08-20 |
DE60328853D1 (en) | 2009-10-01 |
ATE440182T1 (en) | 2009-09-15 |
ATE440183T1 (en) | 2009-09-15 |
EP1382750B1 (en) | 2009-08-19 |
ES2331239T3 (en) | 2009-12-28 |
GB2391036A (en) | 2004-01-28 |
GB2391036B (en) | 2005-05-04 |
EP1382751B1 (en) | 2009-08-19 |
GB2391035A (en) | 2004-01-28 |
GB0316860D0 (en) | 2003-08-20 |
DE60328854D1 (en) | 2009-10-01 |
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