WO1996014474A1 - Compaction of soil - Google Patents
Compaction of soil Download PDFInfo
- Publication number
- WO1996014474A1 WO1996014474A1 PCT/GB1995/002616 GB9502616W WO9614474A1 WO 1996014474 A1 WO1996014474 A1 WO 1996014474A1 GB 9502616 W GB9502616 W GB 9502616W WO 9614474 A1 WO9614474 A1 WO 9614474A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- impact
- mass
- frame
- compactor
- compactor mass
- Prior art date
Links
Classifications
-
- 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
- E02D3/026—Improving by compacting by rolling with rollers usable only for or specially adapted for soil compaction, e.g. sheepsfoot rollers
Definitions
- THIS invention relates to the compaction of soil and in particular to the compaction of soil using an impact roller or impact compactor mass.
- impact roller refers to a soil compaction machine including a compactor mass of non-round shape which, when towed over a soil surface, produces a series of periodic blows on the soil surface.
- the compactor mass of an impact roller has a series of spaced apart, salient points on its periphery. Each such salient point is followed by a re-entrant portion of the periphery and each re-entrant portion is followed in turn by a compacting face.
- the mass has equi-angularly spaced salient points 1, re-entrant portions 2 adjacent the salient points 1, and radiused compacting faces 3 between each re-entrant portion 2 and the next salient point 1.
- the mass is mounted on an axle 4 and is towed in the direction of the arrow 5 by a suitable tractor.
- the towing force causes the mass to rise up on each salient point 1 in turn, as illustrated by Figure 1(b), and then to strike a blow on the surface 6 of the soil as the relevant compacting face 3 falls down on that surface.
- the coupling between the tractor and the compactor mass is resilient in nature to allow for the necessary forward and downward falling motion undergone by the mass as it passes over each salient point.
- the letter R refers to the radius from the axle 4 to the extremity of a salient point 1
- the letter r refers to the radius from the axle 4 to the surface of the compacting face 3.
- Potential energy is created by raising the mass, about the salient point 1, through a distance of R-r, as illustrated by Figure 1(b), and the stored potential energy can be quantified as Mg(R-r) Joules where M is the mass in kilograms, g is the gravitational constant in m/sec 2 , and R and r are expressed in metres.
- the potential energy stored in the mass when it rises on its salient point, the centre of mass then being raised 0,15m above its lowest position, is 0,15m x 10 000kg x 9,81m s 2 14 715 Joules, which is nominally stated as 15kJ.
- impact compactor machines with energy values of between 10 and 25U are now commonly used, depending on the nature of the soil and the degree of compaction required.
- Figure 2 of the accompanying drawings illustrates graphically a relationship between the number of compactor blows and the amount of surface settlement of the soil for a typical soil.
- the amount of surface settlement is a measure of the degree to which soil density is improved and also the depth below the surface to which the improvement in soil density takes place.
- Two curves are shown in Figure 2, one for a mass designed to produce 15kJ of impact energy at each blow and another for a mass designed to produce 25kJ of impact energy at each blow. In each, the curve flattens out once a certain surface settlement has been achieved so that, after a certain number of blows the amount of surface settlement hardly varies irrespective of the number of further blows that are applied to the soil.
- the curve for the 25kJ mass is initially somewhat steeper than that for the 15kJ mass i.e. a greater surface settlement is achieved with fewer blows in the case of the 25kJ mass than in the case of the 15kJ mass during the initial stages of compaction.
- a further circumstance in which it would be an advantage for the operator to be able to vary the value of energy per blow during operation is where the soil is too weak to sustain a high energy impact blow.
- This invention provides an impact compaction apparatus for compacting a soil surface, the apparatus comprising a wheeled frame, at least one impact compactor mass connected rotatably to the frame for delivering periodic impact blows to the soil surface when the frame is moved over the surface, and means acting between the frame and the compactor mass for applying a variable vertical force to the impact compactor mass, thereby to vary the blow energy delivered to the soil surface at each impact blow.
- the force applying means can apply a variable upward force to the compactor mass, a variable downward force to the mass, or it may be capable of applying both variable upward and downward forces to the mass.
- the force applying means has resilience.
- the force applying means comprises an air spring and means for supplying air at different pressures to the spring.
- the force applying means may comprise an hydraulic spring in the form of a cylinder or ram, possibly of double-acting type.
- an accumulator storing gas under pressure, in the apparatus.
- the force applying means does not necessarily act directly on the compactor mass.
- the force applying means acts between the frame and an axle on which the compactor mass is mounted.
- the force applying means acts with a vertical component of force between the frame and the axle.
- the force applying means need not necessarily be vertically acting, as long as its line of application is such as to produce a vertical. component of force.
- the force applying means may be sufficient for the or each compactor mass to be lifted clear of the soil surface so that transportation thereof can take place without the application of impact blows to the soil surface.
- the force applying means may be responsive to an automatic sensor operatively associated with the steering mechanism of a traction unit used to tow the compactor mass, or the steering mechanism of the vehicle itself in the case of a self-powered apparatus, the sensor being arranged to cause the force applying means to raise the compactor mass or masses clear of the soil surface in response to a predetermined change in steering direction.
- the frame may be in the form of a drawn or self-powered carriage, with a resilient linkage for connecting the compactor mass to the carriage.
- the linkage may comprise a drag link connected rigidly to the axle at one end, a drop link which is pinned at one end to the opposite end of the drag link and at an intermediate point to the carriage, and a spring acting between the carriage and the opposite end of the drop link.
- the spring is conveniently an hydraulic spring.
- the apparatus may comprise more than one compactor mass.
- Figure 1 (a) and 1 (b) show a typical three-sided impact compactor mass in the impact position and the energy storage position respectively;
- Figure 2 shows a graph of surface settlement against compactor blows for different energy values of a typical compactor mass such as that seen in Figures 1(a) and 1(b);
- Figure 3 shows a partly sectioned plan view of an impact compactor according to the present invention
- Figure 4 shows a side elevation of the impact compactor seen in Figure 3, with one compactor mass removed to reveal working components;
- Figure 5 shows a detail of hydraulic componentry.
- FIGs 3 and 4 illustrate relevant parts of an impact compactor according to the present invention.
- the compactor has a dual mass system with two identical three-sided compactor masses 10 connected to one another by a common axle 14.
- each mass 10 has three salient points 11 each followed, in the order of movement, by a re-entrant portion 12 and a radiused compaction zone or compacting face 13.
- the impact compactor of Figures 3 and 4 includes a frame or carriage 15 fitted with ground engaging wheels 16.
- the forward end of the carriage 15 is connected solidly to a wheeled traction unit 17.
- the axle 14 is connected to the carriage 15 by a resilient linkage which includes a draglink 18, a droplink 19 and an hydraulic spring 20 applying a traction force.
- One end of the draglink 18 is connected fast to the axle 14.
- the droplink 19 is pinned to the other end of the draglink 18 at a point 9 and to the carriage 15 at a point 21.
- the hydraulic traction spring 20 acts between the traction unit 17 and the upper end of the droplink 19.
- the traction spring 20 applies a traction force to the upper end of the droplink 19.
- the illustrated linkage of components 18, 19 and 20 is a resilient linkage which provides a connection between the axle 14 and the traction unit 17 and hence the carriage 15. The linkage enables the axle 14 to move fore and aft as well as up and down relative to the carriage 15 as the compactor masses 10 rotate on the axle 14 in use.
- the device 22 is an air spring of a type commonly used in heavy duty vehicles for suspension control and is capable of accommodating fore and aft movement of the axle 14 relative to the carriage 15.
- Air under pressure is supplied via a flexible hose 23 to the air spring 22 by a compressor 42 mounted in practice on the traction unit 17.
- a multi-position control valve 24 for the compressor 42 is in practice mounted within reach of the traction unit operator. By operating the valve 24, the operator is able to vary the air pressure in the air spring 22, and accordingly the amount of uplift applied via the drag link to the axle with a corresponding reduction in the impact energy applied to the soil surface by the compactor masses.
- an hydraulic ram 26 is pivotally connected to the extremity of a cantilever beam 27 forming an integral part of the traction unit 17.
- the piston rod of the ram 26 exerts a downward thrust upon the drag link 18 at a pivot point 28.
- the details of a typical ram 26 are illustrated in Figure 5.
- the cylinder 25 of the ram 26 is pivoted to the cantilever beam 27 by a pair of stub shafts 29 protruding from the cylinder casing.
- the piston rod 30 is connected to a piston 31 which is reciprocable in the cylinder and which is fitted with an annular wear strip 32 that centralises the piston rod 30 relative to the cylinder bore.
- a pressure seal 43 acts between the cylinder and the piston rod.
- An aperture 33 passes through the piston so as to allow hydraulic fluid in the cylinder unrestricted access to both sides of the piston.
- Hydraulic fluid is able to flow in and out of the cylinder 25 through a port 34 connected to the port 37 of an hydraulic accumulator 35.
- the accumulator 35 is of a generally conventional type and accommodates a volume of inert gas 36 under pressure, typically within a neoprene bladder (not shown). The gas ensures that pressure is maintained in the hydraulic fluid 41 with the result that a nett downward force is exerted on the piston 31 and piston rod 30.
- a pressure sensitive gauge 38 indicates the hydraulic pressure. Alternatively, the gauge may be calibrated to indicate the downward thrust applied by the piston rod or even to indicate actual energy per blow. Pressure in the hydraulic system can be increased by opening a valve 39, accessible to the operator, to admit hydraulic fluid from a pressure source 40, typically an hydraulic pump.
- the valve 39 has three positions. By selection of the second, or neutral position, the fluid flow is shut off so that system pressure is maintained constant, and by selection of the third position, fluid is drained back to the reservoir tank 44, thereby reducing the system pressure and hence the thrust exerted by the piston rod 30.
- a further practical benefit which arises from being able to effect a rapid change in energy is that with a reduction of energy by reducing the downward force of the masses on the ground the drawbar pull required for the traction wheels to pull the masses up from a compacting face onto a salient point is correspondingly reduced. Once the masses pass over the top dead centre position traction becomes easier, it being possible to restore the full load of the masses while the impact roller is in motion.
- the downwardly acting thrust means in this example provided by the hydraulic system described above, can be provided on its own or in conjunction with the upwardly acting thrust means, in this example provided by the air spring 22. Likewise, the upwardly acting thrust means may be provided on its own.
Landscapes
- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Structural Engineering (AREA)
- Agronomy & Crop Science (AREA)
- Environmental & Geological Engineering (AREA)
- Soil Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Mining & Mineral Resources (AREA)
- Paleontology (AREA)
- Civil Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Road Paving Machines (AREA)
Abstract
Description
Claims
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
DE69530008T DE69530008T2 (en) | 1994-11-07 | 1995-11-07 | COMPACTION |
EP95936635A EP0839232B1 (en) | 1994-11-07 | 1995-11-07 | Compaction of soil |
GB9709165A GB2310179B (en) | 1994-11-07 | 1995-11-07 | Compaction of soil |
AU38493/95A AU3849395A (en) | 1994-11-07 | 1995-11-07 | Compaction of soil |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB9422415.1 | 1994-11-07 | ||
GB9422415A GB9422415D0 (en) | 1994-11-07 | 1994-11-07 | Compaction of soil |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1996014474A1 true WO1996014474A1 (en) | 1996-05-17 |
Family
ID=10764000
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/GB1995/002616 WO1996014474A1 (en) | 1994-11-07 | 1995-11-07 | Compaction of soil |
Country Status (6)
Country | Link |
---|---|
EP (1) | EP0839232B1 (en) |
AU (1) | AU3849395A (en) |
DE (1) | DE69530008T2 (en) |
ES (1) | ES2194926T3 (en) |
GB (2) | GB9422415D0 (en) |
WO (1) | WO1996014474A1 (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE19648593A1 (en) * | 1996-11-23 | 1998-06-04 | Wacker Werke Kg | Single- or twin-axle vibratory roller with non-cylindrical tyres |
WO1998051866A1 (en) * | 1997-05-15 | 1998-11-19 | Compaction Technology (Soil) Limited | Impact compactor |
JP2017002665A (en) * | 2015-06-15 | 2017-01-05 | 鹿島建設株式会社 | Compaction machine and compaction method |
CN115094716A (en) * | 2022-07-22 | 2022-09-23 | 徐工集团工程机械股份有限公司道路机械分公司 | Road roller working device and road roller |
Families Citing this family (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102018006902A1 (en) | 2018-08-30 | 2020-03-05 | Forschungs- Und Transferzentrum Leipzig E.V. An Der Hochschule Für Technik, Wirtschaft Und Kultur Leipzig | Vibration exciter for roller device for soil compaction |
CN111719539A (en) * | 2020-06-30 | 2020-09-29 | 孙秋月 | Ditch tamping device for highway engineering construction |
Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2909106A (en) * | 1953-08-17 | 1959-10-20 | Berrange Aubrey Ralph | Impact rolling or tamping machines for the compaction of loose materials, such as road surfaces |
CH436371A (en) * | 1965-05-31 | 1967-05-31 | Trachsel Jakob | Soil compactor |
FR2038168A1 (en) * | 1969-04-02 | 1971-01-08 | South African Inventions | |
DE2359375A1 (en) * | 1973-11-28 | 1974-06-12 | South African Inventions | COMPACTION DEVICE |
FR2268114A1 (en) * | 1974-04-19 | 1975-11-14 | South African Inventions | |
DE2822441A1 (en) * | 1977-05-25 | 1978-12-07 | South African Inventions | COMPRESSOR ROLLER DEVICE AND METHOD FOR OPERATING THE SAME |
EP0017511A1 (en) * | 1979-04-09 | 1980-10-15 | Aubrey Ralph Berrange | Compactor |
-
1994
- 1994-11-07 GB GB9422415A patent/GB9422415D0/en active Pending
-
1995
- 1995-11-07 DE DE69530008T patent/DE69530008T2/en not_active Expired - Fee Related
- 1995-11-07 GB GB9709165A patent/GB2310179B/en not_active Expired - Lifetime
- 1995-11-07 EP EP95936635A patent/EP0839232B1/en not_active Expired - Lifetime
- 1995-11-07 WO PCT/GB1995/002616 patent/WO1996014474A1/en active IP Right Grant
- 1995-11-07 AU AU38493/95A patent/AU3849395A/en not_active Abandoned
- 1995-11-07 ES ES95936635T patent/ES2194926T3/en not_active Expired - Lifetime
Patent Citations (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2909106A (en) * | 1953-08-17 | 1959-10-20 | Berrange Aubrey Ralph | Impact rolling or tamping machines for the compaction of loose materials, such as road surfaces |
CH436371A (en) * | 1965-05-31 | 1967-05-31 | Trachsel Jakob | Soil compactor |
FR2038168A1 (en) * | 1969-04-02 | 1971-01-08 | South African Inventions | |
DE2359375A1 (en) * | 1973-11-28 | 1974-06-12 | South African Inventions | COMPACTION DEVICE |
FR2268114A1 (en) * | 1974-04-19 | 1975-11-14 | South African Inventions | |
DE2822441A1 (en) * | 1977-05-25 | 1978-12-07 | South African Inventions | COMPRESSOR ROLLER DEVICE AND METHOD FOR OPERATING THE SAME |
EP0017511A1 (en) * | 1979-04-09 | 1980-10-15 | Aubrey Ralph Berrange | Compactor |
Cited By (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE19648593A1 (en) * | 1996-11-23 | 1998-06-04 | Wacker Werke Kg | Single- or twin-axle vibratory roller with non-cylindrical tyres |
DE19648593C2 (en) * | 1996-11-23 | 2000-10-12 | Wacker Werke Kg | Vibratory roller |
WO1998051866A1 (en) * | 1997-05-15 | 1998-11-19 | Compaction Technology (Soil) Limited | Impact compactor |
AU732609B2 (en) * | 1997-05-15 | 2001-04-26 | Compaction Technology (Soil) Limited | Impact compactor |
JP2017002665A (en) * | 2015-06-15 | 2017-01-05 | 鹿島建設株式会社 | Compaction machine and compaction method |
CN115094716A (en) * | 2022-07-22 | 2022-09-23 | 徐工集团工程机械股份有限公司道路机械分公司 | Road roller working device and road roller |
Also Published As
Publication number | Publication date |
---|---|
DE69530008T2 (en) | 2004-03-04 |
EP0839232B1 (en) | 2003-03-19 |
AU3849395A (en) | 1996-05-31 |
GB2310179A (en) | 1997-08-20 |
GB9422415D0 (en) | 1995-01-04 |
DE69530008D1 (en) | 2003-04-24 |
EP0839232A1 (en) | 1998-05-06 |
GB2310179B (en) | 1998-02-25 |
GB9709165D0 (en) | 1997-06-25 |
ES2194926T3 (en) | 2003-12-01 |
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