CA1136870A - Hydraulic method of soil compaction and apparatus therefore - Google Patents
Hydraulic method of soil compaction and apparatus thereforeInfo
- Publication number
- CA1136870A CA1136870A CA000357176A CA357176A CA1136870A CA 1136870 A CA1136870 A CA 1136870A CA 000357176 A CA000357176 A CA 000357176A CA 357176 A CA357176 A CA 357176A CA 1136870 A CA1136870 A CA 1136870A
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- Canada
- Prior art keywords
- water
- soil
- nozzle
- point source
- flow
- 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.)
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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
- E02D3/046—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
-
- 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
-
- 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
- E02D3/10—Improving by compacting by watering, draining, de-aerating or blasting, e.g. by installing sand or wick drains
-
- 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
- E02D3/12—Consolidating by placing solidifying or pore-filling substances in the soil
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- 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 Structures (AREA)
Abstract
TITLE
HYDRAULIC METHOD OF SOIL COMPACTION
AND APPARATUS THEREFORE
INVENTOR
Raffaele MEO
ABSTRACT
The method and apparatus of water jetting is disclosed; namely, a method of saturating a clay backfill or the like with water so that the hydraulic action cooperates with the lumps of clay of the backfill and hence causes better adhesive compaction of the soil. It includes also, in another embodiment, a method of draining the soil.
Further, an apparatus for accomplishing the methods includes a nozzle having a hollow interior and a plurality of orifices which communicate the interior to the exterior and a source of water supply for flowing water into the interior of the nozzle and hence out the orifices thereof at preferred predetermined pressures of 200 to 400 Kilo Pascals (KPa.) although it may be used throughout the range of 0 to 700 KPa.. The method include applying a force to the nozzle while water is eminating therefrom so that the nozzle penetrates into the soil to a predetermined depth and then slowly lifting the nozzle under controlled conditions while allowing the water to eminate from the orifices thereof so as to saturate the adjacent soil successively until the whole depth of the trench is saturated with water.
HYDRAULIC METHOD OF SOIL COMPACTION
AND APPARATUS THEREFORE
INVENTOR
Raffaele MEO
ABSTRACT
The method and apparatus of water jetting is disclosed; namely, a method of saturating a clay backfill or the like with water so that the hydraulic action cooperates with the lumps of clay of the backfill and hence causes better adhesive compaction of the soil. It includes also, in another embodiment, a method of draining the soil.
Further, an apparatus for accomplishing the methods includes a nozzle having a hollow interior and a plurality of orifices which communicate the interior to the exterior and a source of water supply for flowing water into the interior of the nozzle and hence out the orifices thereof at preferred predetermined pressures of 200 to 400 Kilo Pascals (KPa.) although it may be used throughout the range of 0 to 700 KPa.. The method include applying a force to the nozzle while water is eminating therefrom so that the nozzle penetrates into the soil to a predetermined depth and then slowly lifting the nozzle under controlled conditions while allowing the water to eminate from the orifices thereof so as to saturate the adjacent soil successively until the whole depth of the trench is saturated with water.
Description
1~3~t~70 This invention relates to a method of hydraulic compaction of soil via water jetting and to apparatus to accomplish the same.
For years some people associated with the installation of sewers for municipalities within Essex County in Ontario, Canada, have been proposing the use of water as an innovative way of compacting native clay backfill of utility trenches. This method has become known as "water jetting".
Although water jetting is generally acknowledged to be a cheaper method of compacting trench backfill when compared to mechanical equipment, its use has only been allowed on a very limited scale, and usually at the contractor's risk due to the fact that much is unknown about the mechani~m at work.
This invention deals with both an apparatus for and a method to carry out water jetting. It uses a pressurized water jet to apply compactive energy to soil.
Basically, water i9 injected into the backfilled trench beneath the upper surface of the soil until the soil is completely saturated. Then compaction is achieved through the action of the water (soil vibration; breakdown of clay lumps; reduction of cohesive forces; seepage forces) that encourages the consolidation of the backfill under its own weight and that of water.
When water jetting is carried out properly, the results obtained with this method are at least equivalent to those obtained with only mechanical compaction, while the cost is significantly reduced. Unfortunately, municipal-ities have been reluctant to allow it to be used exten-sively, mainly because no standards or specifications are in existence, and until now no one seemed to be aware of
For years some people associated with the installation of sewers for municipalities within Essex County in Ontario, Canada, have been proposing the use of water as an innovative way of compacting native clay backfill of utility trenches. This method has become known as "water jetting".
Although water jetting is generally acknowledged to be a cheaper method of compacting trench backfill when compared to mechanical equipment, its use has only been allowed on a very limited scale, and usually at the contractor's risk due to the fact that much is unknown about the mechani~m at work.
This invention deals with both an apparatus for and a method to carry out water jetting. It uses a pressurized water jet to apply compactive energy to soil.
Basically, water i9 injected into the backfilled trench beneath the upper surface of the soil until the soil is completely saturated. Then compaction is achieved through the action of the water (soil vibration; breakdown of clay lumps; reduction of cohesive forces; seepage forces) that encourages the consolidation of the backfill under its own weight and that of water.
When water jetting is carried out properly, the results obtained with this method are at least equivalent to those obtained with only mechanical compaction, while the cost is significantly reduced. Unfortunately, municipal-ities have been reluctant to allow it to be used exten-sively, mainly because no standards or specifications are in existence, and until now no one seemed to be aware of
- 2 ;'O
a satisfactory water jetting apparatus, or method of application thereof, e.g. technique.
A paper published in 1978 by Dr. J.T. Laba and Dr.
M.A.F. Sheta, both of the University of Windsor, Windsor, Canada, reported on an in depth laboratory study dealing with the effect of selected parameters on the behaviour of a soil sample. The study concluded that water jetting is more effective in backfills with mixed lump size: in deeper trenches, with higher jetting pressure; and, with increased seepage forces and a smaller jetted area per jet. The effectiveness is decreased by jetting in layers and by increasing the amount of granular material in the backfill.
Although the investigation seems to be extensive, its authors cautioned that the laboratory results could only be referred to as "trends" and could not be used as a direct representation of real field behaviour. This was a laboratory study and no attempt was made to develop a full scale jetting apparatus or a method to employ commercially.
A survey of water jetted trenches carried out in 1979 reached the following conclusions:
Water jetting would be adequate in preventing long term settlement: that trenches, which have been water jetted in the last five years, have not undergone any appreciable settlement as of yet; and, that water jetting is ineffective in compacting granular soils. Although the results of the study are very encouraging, it is most unfortunate that only general descriptions and no details are available reyarding the water jetting method and appropriate apparatus in each case.
In fact, only rudimentary methods and equipment were used.
The prior art presently consists of the following:
f) MECHANICAL COMPACTION OF CLAY BACKFILL
During excavation the native clay is broken into lumps with individual density equivalent to the original undisturbed soil. When these lumps are replaced back into the trench a~ backfill, a large volume of voids is created.
In order to minimize the voids, mechanically, a heavy weight and kneading action is applied to relatively thin layers or strata of soil (0.30 to 0.60 m). This process requires a shear failure to each lump and its remoulding into a new shape which fills an adjacent void.
Immediately following placement and compaction, each lump is stable and bears on th~ underlying lumps with several areas of contact. When seepage of rain water and runoff reach these clay lumps, the small contact areas are softened, and they now are no longer able to bear the overburden since they are destabilized. Through a series of shear and creep failures, the soil lump undergoes deformation, and downward movement, as do adjacent lumps, until the softened areas of contact are large enough to support the overburden. At this stage, no further significant settlement will occur. Unfortunately, by this time large settlements have already occurred which express themselves in great surface depressions and resulting in a very uneven pavement and even possibly roadway structure failure; or, when this approach is used for new sewages, possible failure of the new sewer lines.
It is an object of the invention to improve back-fill compaction, improve safety, while at the same time to reduce costs.
In order to better understand the functions of the backfill mass at various depths, it is desirable to divide it into three zones.
. o Zone A: This backfill is required for the bedding and cover of the buried service.
Normally a granular ma~erial is used, with its degree of compaction controlled by the support requirements of the service. If water jetting is to be used this zone should consist of a uniform granular material, such as clear stone, so that a free-draining bed is provided.
Zone B: This zone fills the area between the pavement structure and the pipe cover. Its main requirement is that it be stable under its own weight, traffic vibrations and downward water seepage forces.
Zone C: This zone forms part of the pavement structure. It must be capable of distributing part of the traffic loading and remain stable under the weight of the over-burden and applied pavement loads.
The zone which occupies the largest volume is Zone B. This is the ideal plac~ to use native clay backfill and water jetting, since it would eliminate settlement problems and provide for a more economical and convenient backfilling operation.
The invention thus contemplates hydraulic compaction as a method of soil compaction. It achieves certain advantages.
Cost: The cost reduction is one of the most significant advantages of water jetting (hydraulic compaction) when compared to mechanical compaction. Actual savings based on 1980 costs is up to 19~ of the total cost of a sewer .~
project. Up to 70~ of mechanical con,paction cost could be saved.
Safety: Water jetting can be safer than mechanical compaction since men and machinery are not required to enter the trench behind the pipe laying operation. In addition, the trench can be backfilled very quickly, and right to the surface, thus eliminating the danger a deep excavation poses to workmen, pedestrians and vehicular traffic.
Subgrade Vniformity: When native material is used, this method of compaction restores the entire subgrade to its original state before excavation, eventually eliminating any trace of the interphase between the trench and its surroundings. Because of the properties of the backfill material and the undisturbed soil are very similar, any settlement will be very small and uniform in nature. This cannot be ~aid for mechanical compaction, where large differential settlements are a very real possibility.
Interference with Traffic: Since mechanical equipment is not required to enter the excavation, much narrower trenches can be used when water jetting. This results in less excavation, less disposal of excess material and less surface restoration. This not only contributes to cost -savings, but also makes for a much faster operation, therefore causing less inconvenience for the regular road user.
More Complete Compaction: In the majority of cases mechanical compaction cannot adequately ~ J
compact the backfill adjacent to the trench walls. Water jetting eliminates this problem, as the water is able to seep into all voids, including those nearest the walls.
There may appear to be some disadvantages or inconveniences to hydraulic compaction of soil.
Greater Time Delay: This delay occurs because normally an entire section of sewer is completed before the water jetting is carried out. Also some time must be allowed for the backfill to settle and regain sufficient bearing strength before traffic can be allowed to travel over the trench (this can vary from a few days to over a week). This would not to be an unreasonable time delay, since similar delays are common to mechanical compaction.
High Residual Moisture Content: After water jetting the moisture content of the backfill decreases from the saturation value to a value which is approximately 4% to 6% above the Proctor optimum value. This value is constant for any particular soil, and is known as the field capacity or the specific retention, the point below which the water cannot be drained. Although those skilled in the art have generally regarded this as a disadvantage it should be noted that a flexible pavement will perform better on a soft uniform grade than on a hard non-uniform ~ubgrade, hence this may actually be an advantage. Further, it has been suggested that the best mechancial compaction results are obtained at a moisture content approximately 4~ above the Proctor , O
optimum. The high moisture content also precludes any significant amount of infiltration and the associated settlement.
Freezing Weather: Water jetting cannot be carried out during periods of sub-freezing temperatures.
As a result, the winter months are lost for sewer construction. (This, of course, does not apply to areas which do not require restoration until the following spring or summer.) Additional Bac~filling: Even if the backfill level before jetting is several feet above the surrounding ground, once the water jetting process has been carried out the trench surface settles to a level below the ground elevation. Additional clay or granular backfill must then be placed and compacted mechanically.
The invention therefore contemplates, firstly, an appara~us for injecting, systematically, into soil, water whereby the adjacent soil is compacted with the aid of hydraulic forces, the apparatus comprising:
(a) a hollow conical member defining a hollow interior extending into a cylindrical member as an extension thereof, the members defining a plurality of apertures that communicate the hollow interior to its exterior;
(b) a source of water supply; and, ~c) a flexible conduit interconnecting and communicating the nozzle with the water ~upply.
Secondly, the invention also contemplates a method of compacting soil comprising the steps of:
(a) applying to a point source, a flow of water, rf () and to the point source, a downward force, whereby, as result of the flow of water, and the weight, the point source tends to traverse into the depth of the ground;
(b) terminating at a prescribed depth the downward force and hence further penetration of the point source;
(c) applying thereto an upward force, whereby, under the continuous flow of the water out of the point source as it slowly migrates to the surface causing the soil adjacent thereto to be inundated with water whereby, the soil is compacted by hydraulic forces.
Additionally it may include drainage of the injected water through a sewer pipe or the pumping of the water out from the injected region and in appropriate circumstances restoration of the surface (Zone C) by mechanical compaction.
The invention will now be described by way of example and reference to the accompaning drawings in which:
Figure 1 is a perspective of a nozzle defining its orifices which provides the hydraulic flow to adjacent soil.
Figure 2 ix a diagramatic perspective for explanation of the nozzle of Figure 1 in soil and supplying hydraulic fluid thereto.
Figure 3 is a typical connection of the nozzle of Figures 1 and 2 to a source of water supply with an additional pressure creating device for hydraulic fluid.
Figures 4, 5, 6, 7, and 8 are exemplary drawings in elevation, of the nozzle, in Figure 4, having penetrated to the base of a region ~Zone B) of backfill, and in Figures 5, 6 and 7 being slowly forced up under the influence of .
g force F while at the same time eminating water, and in Figure 8, the purging of the subjacent saturated granular regions A and B of water whereby compaction i5 ensured.
Figures 9 and 9a are cross section elevational views of the steps by which the apparatus is utilized and the method is accomplished.
Figures 10 and 11, respectively, are diagramatic representations of soil samples with clumps 1 through 10 shown, as at Figure 10, with interstelar regions or spacial regions prior to compaction, and at Figure 11 with compaction where those regions are destroyed.
~ igures 12 and 13 are a diagramatic represen-tations of adjacent soil clumps with hydraulic surface tension forces thereon, that occur at a soil/water interphase.
Referring now to Figure 1, a nozzle 30 is generally shown located in region 30' and is of conical structure having a plurality of orifices 0, and adjacent thereto and communicating therewith, cylindrical member 30'' both which define a hollow interior 33. The hollow interior 33 communicates, as more clearly seen in Figure 3, to a source of water supply, for instance a hydrant 40 by virtue of a hose 50. It may be convenient, when for example the hydrant 40 is incapable of supplying a sufficiently high volume of water under a significant pressure, to interpose a pump 60 and hence to force feed the nozzle 30. It will now be apparent to those skilled in the art th~t other appropriate water sources may be used with equal success such as a river, reservoir, etc. provided, however, that the volume of water and its head or pressure is satisfactory.
Preferably, to monitor the function of the apparatus, the upper terminal of the nozzle 30, has a ','O
pressure gauge 35 associated therewith which reads the hydraulic pressure of the water in the hose 50 and in the nozzle 30 and is thereby ideal for water reading.
Figure 4 depicts, not in total detail, a section through a manhole M, the manhole communicating to a sewer S
which has been recently imbedded in the ground and to which an overburden, which may be backfill, generally shown as 70 has been applied. The overburden 70 generally forms three regions, from top to bottom, Zones C, B and A as previously identified at page 5 of this disclosure.
The manhole has, at its base, and just super-adjacent to the sewer S, an orifice in which is placed a removable plug P. Depending on the situation, this orifice may or may not be plugged during the injection of water into the backfill. Since Zone A is granular material it covers the plug P, the removal of the plug P will purge the zone A
of any moisture or water that may subsequently be applied thereto as will hereinafter be explained.
Referring to Figure 4, the nozzle 30 is first placed on top of the ground and the water is allowed to outflow the nozzle 30. A downward force F is applied to the nozzle causing the nozzle to reverse and to penetrate into the ground so as to eventually locate itself as shown in Figure 4. Water jetting now commenced by the continuation of the water flow will now be described. The nozzle 30 for the commencement of water jetting is located in the lowest regions of Zone A, which is composed of granular material and immediately overlies the sewer S. Optionally, if penetration into the granular material is too difficult, the nozzle may be located on the upper surface of Zone A.
Thereupon Zone A is allowed to be flooded and when full flooding occurs the pressure gauge 35 will indicate a slight 113~ rt0 variation in water pressure in the conduit 50 indicating to the operator (not shown) the effect of water inundation in Zone A upon the flow thereof from the nozzle and hence increasing resistance thereto. At this time the operator knows that Zone A has been flooded and causes to be imparted onto the nozzle 30 or stem an upward force which is depicted as F in Figures 6 and 7. This upward force F may be caused by mechanical device such as the lift, crane or other device, or also as conveniently by a human being, the nozzle 30 is slowly lifted up through the overburden 70, through Zone B, while at the same time water 80 eminates from the various pores in the nozzle as depicted in Figures 6 and 7.
When the overburden 70 in Zone B is totally saturated, and the pores of the nozzle reach the surface of Zone C as seen in Figure 7, the supply of water from the hydrant 40 may be terminated and the nozzle lifted out of contact with the ground.
At this point in time the region beneath the nozzle and to a substantial degree, up and down the trench length are inundated with water. When, for instance, the trench has a width of approximately 2 metres, saturation caused by such nozzle will extend up and down the trench length for about 2 to 4 metres on either side o~ the location of the nozzle. The actual extent of saturation, and therefore settlement depends upon the porosity of the soil, the type of soil, and the lump size of the soil. Such event is depicted in Figure 9, by the phantorn nozzle 30R.-At that location, 30R, the entire underlying overburden 70 is saturated. The nozzle may then be moved to an adjacent '0 location as for example 30C and the entire process is repeated until the entire length of trench has been completely water jetted. ~ne nozzle location 30C in Figure 9 depicts an intermediate interhole of water jetting at location 30C where complete saturation has taken place of Zone A and Zone B only the lower half thereof has been saturated.
The phantom location 30L is the next jetting location. When that location has been water jetted, the full extent between the two manholes M will have been water jetted. Referrins now to figure 8 the plug P may then be removed and Zone A purged of water. Since Zone A is granular the total Zone A will be purged. This will cause a drainage from the superadjacent Zone B and also from Zone C and will encourage compaction. After this has occurred and referring to Figure 8 now, the upper crust 45 begins to fall since compaction is occurring.
Thus the water flows into the sewer S through the orifice in the bottom of the manhole when the plug P in the manhole is removed, this is depicted in Figure 8. Thi~
induces further compaction of t~e soil whereby the upper crust of the backfill, takes on that new profile shown in Figure 8. Normally the extent of the depression thereby created in the upper surface when the trench depth is more or less then 4 metres, is to an extent of 0.60 to 0.90 metres, more or less in depth.
Now again referring to Figures 1 and 2 and to an explanation of the hydraulic reactions caused by the nozzle 30 as indicated in Figure 2, the arrow indicates the flow of water into the nozzle. That flow of water gushes out of the plurality of orifices in the nozzle indicated as 0. That water flow traverses, for example, according to the arrows and dash lines indicated in Figure 2, eroding certain regions 43 of the various lumps of soil 45. Erosion from regions 43 traverses into the spaces 55 and floods the same with a mixture of soil and water. In this way, the hydraulic action causes the mi~ration of soil into the inner spacial regions between the adjacent lumps of soil and hence fills the voids defined by those lumps. This causes compaction. Each jet of water gushins from each orifice has a force which vibrates, breaks down and forces the soil lumps closer together. This again causes compaction. Once the water is in contact with the soil, it causes a reduction in the soil's cohesion, making the lumps soft and not able to resist the compactive forces applied by its own weight and by the seepage forces as the water is drained out of the backfill. Figures 10 and 11 depict lumps 10 of clay prior to water jetting; and after jetting.
It has been found, that ideally, and to deliver the maximum energy the total area defined by the plurality of orifices O in the nozzle 30 varies according to the length and type of conduit 50. For example, for a fire hose, with inner diameter of 60 mm, this total orifice area is in graphæ 7 and 3 which will be discussed hereafter, 30%
and 60~ of the conduit's cross-sectional area, as shown, for hose lengths of 100 metres and 8 metres respectively.
When the plurality of orifice diameters aggregate to an area in excess of the cross-sectional area of cylinder inefficiencies in water compaction are achieved.
The use of the nozzle 30 has the effect of applying water energy in small, concentrated and powerful jets, distributed over a large area evenly and efficiently, so that the soil lumps are broken down, and penetration of water into all bacXfill voids is facilitated.
Numerous modifications will now be apparent to those skilled and practicing in the art. It is not intended to deny a limit to the invention to the exact construction or operation shown, nor to the apparatus described, and accordingly, suitable modifications to both the apparatus and the method is contemplated within the scope of the invention. I do, however, prefer that the inside diameter of the nozzle be at least 40 mm; the aggregate area of the orifices in the nozzle 30 be around 1250 square milllmetres;
and the nozzle length that disposes the orifices (30'') be about 350 mm. The angle of the tip or cone 30' of the orifice thereof should be inclined at approximately 45. In such application the water pressure preferrably ranges between 200 to 400 KPa. and the volume of water consumed will be in the order of 30 litres per second. Pressure ranges from 0 to 700 ~Pa. may be used.
For those skilled and practicing in the art the attached graphs 1 through 7 will be of value in understanding the utility of the invention.
Graph 1 depicts total settlement in centimetres against time after jetting in days under two conditions, the porous nozzle of the type disclosed in this invention, and a full open probe having no aperture. In other words the full opening probe is one whose cross-sectional area or orifice is identical in size to that internal diameter of the hose or conduit feeding the water to it. You will note that more settlement is achieved with the porous nozzle of the invention.
Graph 2 is similar to that of graph 1 except it depicts settlement after a given amount of days as a function of energy emitted by the nozzle. Note that in all cases the majority of the settlement occurs within two days.
Graph 3 plots water jetting force in newtons of the agreggate area of the openings of the orifices 0 as against a cross-sectional area of the hose. You will see that the idealized condition is very close to a ratio .5:1 -that is where maximum energy i8 emitted to the soil.
This is ~hown a second time, with more plotting points, in graph 7.
Graph 4 is a plot of the degree of compaction as a percentage over the energy applied over a given elapsed period of time from 10 days to 10 months as shown.
Graph 5, which is analogous to that of graph 1 and shows the degree of compaction over time plotting the full probe opening and the porous nozzle of the invention. Note that higher degree of compaction is achieved, and more immediately, with the nozzle of the invention.
Graph 6 also plots the porous nozzle of the invention as against the full probe opening on a graph showing vane shear in Kilo Pascals over a lapsed period of time after jetting. Note that a stronger backfill is obtained with the nozzle of the invention.
TO lAL SETTLEMENT, cm o o ~ r~ ~-~ ~
r _ ~ Z r -~t --113~70 TOTAL SETTLEMENT, cm ~ a o ` ~
, ,, 7(1 ~ t l l --t ~ t~
640 ~ ~~~ ~ h- âm 560- _ /
1 E1,--~ Lh: 25m _ 480- / ~
320 ¦ I ~ j \ Lh ~ 70 m / Lll- 100 m ~, 24 0 - ~
~: .
C~ _ Lh: LENGTH OF HOSE - _ O ~ t I I 1- t 1-(AREA OF OPENING) / (AREA GF HOSE) r~r~lnl '70 DEGREE OF COMPACTION %
o ~ ) Cl) r ~ 0 c~
o I I ~ I i. _ I I l l I
s ~0 DEGREE OF CCMPACTION %
a~ o ~ ~ ~ co O ._ . . . ~ t I . I
Q- ~ ~
I ~ I I ~ ~ I- I I
i? l VANE SHEAR, KPa ~ o ~ O
O I I I t ~-O
640 ~ \
/ ~;- 8m s60! ,~
t ' ~ Lh: 25m ,_ ~
a satisfactory water jetting apparatus, or method of application thereof, e.g. technique.
A paper published in 1978 by Dr. J.T. Laba and Dr.
M.A.F. Sheta, both of the University of Windsor, Windsor, Canada, reported on an in depth laboratory study dealing with the effect of selected parameters on the behaviour of a soil sample. The study concluded that water jetting is more effective in backfills with mixed lump size: in deeper trenches, with higher jetting pressure; and, with increased seepage forces and a smaller jetted area per jet. The effectiveness is decreased by jetting in layers and by increasing the amount of granular material in the backfill.
Although the investigation seems to be extensive, its authors cautioned that the laboratory results could only be referred to as "trends" and could not be used as a direct representation of real field behaviour. This was a laboratory study and no attempt was made to develop a full scale jetting apparatus or a method to employ commercially.
A survey of water jetted trenches carried out in 1979 reached the following conclusions:
Water jetting would be adequate in preventing long term settlement: that trenches, which have been water jetted in the last five years, have not undergone any appreciable settlement as of yet; and, that water jetting is ineffective in compacting granular soils. Although the results of the study are very encouraging, it is most unfortunate that only general descriptions and no details are available reyarding the water jetting method and appropriate apparatus in each case.
In fact, only rudimentary methods and equipment were used.
The prior art presently consists of the following:
f) MECHANICAL COMPACTION OF CLAY BACKFILL
During excavation the native clay is broken into lumps with individual density equivalent to the original undisturbed soil. When these lumps are replaced back into the trench a~ backfill, a large volume of voids is created.
In order to minimize the voids, mechanically, a heavy weight and kneading action is applied to relatively thin layers or strata of soil (0.30 to 0.60 m). This process requires a shear failure to each lump and its remoulding into a new shape which fills an adjacent void.
Immediately following placement and compaction, each lump is stable and bears on th~ underlying lumps with several areas of contact. When seepage of rain water and runoff reach these clay lumps, the small contact areas are softened, and they now are no longer able to bear the overburden since they are destabilized. Through a series of shear and creep failures, the soil lump undergoes deformation, and downward movement, as do adjacent lumps, until the softened areas of contact are large enough to support the overburden. At this stage, no further significant settlement will occur. Unfortunately, by this time large settlements have already occurred which express themselves in great surface depressions and resulting in a very uneven pavement and even possibly roadway structure failure; or, when this approach is used for new sewages, possible failure of the new sewer lines.
It is an object of the invention to improve back-fill compaction, improve safety, while at the same time to reduce costs.
In order to better understand the functions of the backfill mass at various depths, it is desirable to divide it into three zones.
. o Zone A: This backfill is required for the bedding and cover of the buried service.
Normally a granular ma~erial is used, with its degree of compaction controlled by the support requirements of the service. If water jetting is to be used this zone should consist of a uniform granular material, such as clear stone, so that a free-draining bed is provided.
Zone B: This zone fills the area between the pavement structure and the pipe cover. Its main requirement is that it be stable under its own weight, traffic vibrations and downward water seepage forces.
Zone C: This zone forms part of the pavement structure. It must be capable of distributing part of the traffic loading and remain stable under the weight of the over-burden and applied pavement loads.
The zone which occupies the largest volume is Zone B. This is the ideal plac~ to use native clay backfill and water jetting, since it would eliminate settlement problems and provide for a more economical and convenient backfilling operation.
The invention thus contemplates hydraulic compaction as a method of soil compaction. It achieves certain advantages.
Cost: The cost reduction is one of the most significant advantages of water jetting (hydraulic compaction) when compared to mechanical compaction. Actual savings based on 1980 costs is up to 19~ of the total cost of a sewer .~
project. Up to 70~ of mechanical con,paction cost could be saved.
Safety: Water jetting can be safer than mechanical compaction since men and machinery are not required to enter the trench behind the pipe laying operation. In addition, the trench can be backfilled very quickly, and right to the surface, thus eliminating the danger a deep excavation poses to workmen, pedestrians and vehicular traffic.
Subgrade Vniformity: When native material is used, this method of compaction restores the entire subgrade to its original state before excavation, eventually eliminating any trace of the interphase between the trench and its surroundings. Because of the properties of the backfill material and the undisturbed soil are very similar, any settlement will be very small and uniform in nature. This cannot be ~aid for mechanical compaction, where large differential settlements are a very real possibility.
Interference with Traffic: Since mechanical equipment is not required to enter the excavation, much narrower trenches can be used when water jetting. This results in less excavation, less disposal of excess material and less surface restoration. This not only contributes to cost -savings, but also makes for a much faster operation, therefore causing less inconvenience for the regular road user.
More Complete Compaction: In the majority of cases mechanical compaction cannot adequately ~ J
compact the backfill adjacent to the trench walls. Water jetting eliminates this problem, as the water is able to seep into all voids, including those nearest the walls.
There may appear to be some disadvantages or inconveniences to hydraulic compaction of soil.
Greater Time Delay: This delay occurs because normally an entire section of sewer is completed before the water jetting is carried out. Also some time must be allowed for the backfill to settle and regain sufficient bearing strength before traffic can be allowed to travel over the trench (this can vary from a few days to over a week). This would not to be an unreasonable time delay, since similar delays are common to mechanical compaction.
High Residual Moisture Content: After water jetting the moisture content of the backfill decreases from the saturation value to a value which is approximately 4% to 6% above the Proctor optimum value. This value is constant for any particular soil, and is known as the field capacity or the specific retention, the point below which the water cannot be drained. Although those skilled in the art have generally regarded this as a disadvantage it should be noted that a flexible pavement will perform better on a soft uniform grade than on a hard non-uniform ~ubgrade, hence this may actually be an advantage. Further, it has been suggested that the best mechancial compaction results are obtained at a moisture content approximately 4~ above the Proctor , O
optimum. The high moisture content also precludes any significant amount of infiltration and the associated settlement.
Freezing Weather: Water jetting cannot be carried out during periods of sub-freezing temperatures.
As a result, the winter months are lost for sewer construction. (This, of course, does not apply to areas which do not require restoration until the following spring or summer.) Additional Bac~filling: Even if the backfill level before jetting is several feet above the surrounding ground, once the water jetting process has been carried out the trench surface settles to a level below the ground elevation. Additional clay or granular backfill must then be placed and compacted mechanically.
The invention therefore contemplates, firstly, an appara~us for injecting, systematically, into soil, water whereby the adjacent soil is compacted with the aid of hydraulic forces, the apparatus comprising:
(a) a hollow conical member defining a hollow interior extending into a cylindrical member as an extension thereof, the members defining a plurality of apertures that communicate the hollow interior to its exterior;
(b) a source of water supply; and, ~c) a flexible conduit interconnecting and communicating the nozzle with the water ~upply.
Secondly, the invention also contemplates a method of compacting soil comprising the steps of:
(a) applying to a point source, a flow of water, rf () and to the point source, a downward force, whereby, as result of the flow of water, and the weight, the point source tends to traverse into the depth of the ground;
(b) terminating at a prescribed depth the downward force and hence further penetration of the point source;
(c) applying thereto an upward force, whereby, under the continuous flow of the water out of the point source as it slowly migrates to the surface causing the soil adjacent thereto to be inundated with water whereby, the soil is compacted by hydraulic forces.
Additionally it may include drainage of the injected water through a sewer pipe or the pumping of the water out from the injected region and in appropriate circumstances restoration of the surface (Zone C) by mechanical compaction.
The invention will now be described by way of example and reference to the accompaning drawings in which:
Figure 1 is a perspective of a nozzle defining its orifices which provides the hydraulic flow to adjacent soil.
Figure 2 ix a diagramatic perspective for explanation of the nozzle of Figure 1 in soil and supplying hydraulic fluid thereto.
Figure 3 is a typical connection of the nozzle of Figures 1 and 2 to a source of water supply with an additional pressure creating device for hydraulic fluid.
Figures 4, 5, 6, 7, and 8 are exemplary drawings in elevation, of the nozzle, in Figure 4, having penetrated to the base of a region ~Zone B) of backfill, and in Figures 5, 6 and 7 being slowly forced up under the influence of .
g force F while at the same time eminating water, and in Figure 8, the purging of the subjacent saturated granular regions A and B of water whereby compaction i5 ensured.
Figures 9 and 9a are cross section elevational views of the steps by which the apparatus is utilized and the method is accomplished.
Figures 10 and 11, respectively, are diagramatic representations of soil samples with clumps 1 through 10 shown, as at Figure 10, with interstelar regions or spacial regions prior to compaction, and at Figure 11 with compaction where those regions are destroyed.
~ igures 12 and 13 are a diagramatic represen-tations of adjacent soil clumps with hydraulic surface tension forces thereon, that occur at a soil/water interphase.
Referring now to Figure 1, a nozzle 30 is generally shown located in region 30' and is of conical structure having a plurality of orifices 0, and adjacent thereto and communicating therewith, cylindrical member 30'' both which define a hollow interior 33. The hollow interior 33 communicates, as more clearly seen in Figure 3, to a source of water supply, for instance a hydrant 40 by virtue of a hose 50. It may be convenient, when for example the hydrant 40 is incapable of supplying a sufficiently high volume of water under a significant pressure, to interpose a pump 60 and hence to force feed the nozzle 30. It will now be apparent to those skilled in the art th~t other appropriate water sources may be used with equal success such as a river, reservoir, etc. provided, however, that the volume of water and its head or pressure is satisfactory.
Preferably, to monitor the function of the apparatus, the upper terminal of the nozzle 30, has a ','O
pressure gauge 35 associated therewith which reads the hydraulic pressure of the water in the hose 50 and in the nozzle 30 and is thereby ideal for water reading.
Figure 4 depicts, not in total detail, a section through a manhole M, the manhole communicating to a sewer S
which has been recently imbedded in the ground and to which an overburden, which may be backfill, generally shown as 70 has been applied. The overburden 70 generally forms three regions, from top to bottom, Zones C, B and A as previously identified at page 5 of this disclosure.
The manhole has, at its base, and just super-adjacent to the sewer S, an orifice in which is placed a removable plug P. Depending on the situation, this orifice may or may not be plugged during the injection of water into the backfill. Since Zone A is granular material it covers the plug P, the removal of the plug P will purge the zone A
of any moisture or water that may subsequently be applied thereto as will hereinafter be explained.
Referring to Figure 4, the nozzle 30 is first placed on top of the ground and the water is allowed to outflow the nozzle 30. A downward force F is applied to the nozzle causing the nozzle to reverse and to penetrate into the ground so as to eventually locate itself as shown in Figure 4. Water jetting now commenced by the continuation of the water flow will now be described. The nozzle 30 for the commencement of water jetting is located in the lowest regions of Zone A, which is composed of granular material and immediately overlies the sewer S. Optionally, if penetration into the granular material is too difficult, the nozzle may be located on the upper surface of Zone A.
Thereupon Zone A is allowed to be flooded and when full flooding occurs the pressure gauge 35 will indicate a slight 113~ rt0 variation in water pressure in the conduit 50 indicating to the operator (not shown) the effect of water inundation in Zone A upon the flow thereof from the nozzle and hence increasing resistance thereto. At this time the operator knows that Zone A has been flooded and causes to be imparted onto the nozzle 30 or stem an upward force which is depicted as F in Figures 6 and 7. This upward force F may be caused by mechanical device such as the lift, crane or other device, or also as conveniently by a human being, the nozzle 30 is slowly lifted up through the overburden 70, through Zone B, while at the same time water 80 eminates from the various pores in the nozzle as depicted in Figures 6 and 7.
When the overburden 70 in Zone B is totally saturated, and the pores of the nozzle reach the surface of Zone C as seen in Figure 7, the supply of water from the hydrant 40 may be terminated and the nozzle lifted out of contact with the ground.
At this point in time the region beneath the nozzle and to a substantial degree, up and down the trench length are inundated with water. When, for instance, the trench has a width of approximately 2 metres, saturation caused by such nozzle will extend up and down the trench length for about 2 to 4 metres on either side o~ the location of the nozzle. The actual extent of saturation, and therefore settlement depends upon the porosity of the soil, the type of soil, and the lump size of the soil. Such event is depicted in Figure 9, by the phantorn nozzle 30R.-At that location, 30R, the entire underlying overburden 70 is saturated. The nozzle may then be moved to an adjacent '0 location as for example 30C and the entire process is repeated until the entire length of trench has been completely water jetted. ~ne nozzle location 30C in Figure 9 depicts an intermediate interhole of water jetting at location 30C where complete saturation has taken place of Zone A and Zone B only the lower half thereof has been saturated.
The phantom location 30L is the next jetting location. When that location has been water jetted, the full extent between the two manholes M will have been water jetted. Referrins now to figure 8 the plug P may then be removed and Zone A purged of water. Since Zone A is granular the total Zone A will be purged. This will cause a drainage from the superadjacent Zone B and also from Zone C and will encourage compaction. After this has occurred and referring to Figure 8 now, the upper crust 45 begins to fall since compaction is occurring.
Thus the water flows into the sewer S through the orifice in the bottom of the manhole when the plug P in the manhole is removed, this is depicted in Figure 8. Thi~
induces further compaction of t~e soil whereby the upper crust of the backfill, takes on that new profile shown in Figure 8. Normally the extent of the depression thereby created in the upper surface when the trench depth is more or less then 4 metres, is to an extent of 0.60 to 0.90 metres, more or less in depth.
Now again referring to Figures 1 and 2 and to an explanation of the hydraulic reactions caused by the nozzle 30 as indicated in Figure 2, the arrow indicates the flow of water into the nozzle. That flow of water gushes out of the plurality of orifices in the nozzle indicated as 0. That water flow traverses, for example, according to the arrows and dash lines indicated in Figure 2, eroding certain regions 43 of the various lumps of soil 45. Erosion from regions 43 traverses into the spaces 55 and floods the same with a mixture of soil and water. In this way, the hydraulic action causes the mi~ration of soil into the inner spacial regions between the adjacent lumps of soil and hence fills the voids defined by those lumps. This causes compaction. Each jet of water gushins from each orifice has a force which vibrates, breaks down and forces the soil lumps closer together. This again causes compaction. Once the water is in contact with the soil, it causes a reduction in the soil's cohesion, making the lumps soft and not able to resist the compactive forces applied by its own weight and by the seepage forces as the water is drained out of the backfill. Figures 10 and 11 depict lumps 10 of clay prior to water jetting; and after jetting.
It has been found, that ideally, and to deliver the maximum energy the total area defined by the plurality of orifices O in the nozzle 30 varies according to the length and type of conduit 50. For example, for a fire hose, with inner diameter of 60 mm, this total orifice area is in graphæ 7 and 3 which will be discussed hereafter, 30%
and 60~ of the conduit's cross-sectional area, as shown, for hose lengths of 100 metres and 8 metres respectively.
When the plurality of orifice diameters aggregate to an area in excess of the cross-sectional area of cylinder inefficiencies in water compaction are achieved.
The use of the nozzle 30 has the effect of applying water energy in small, concentrated and powerful jets, distributed over a large area evenly and efficiently, so that the soil lumps are broken down, and penetration of water into all bacXfill voids is facilitated.
Numerous modifications will now be apparent to those skilled and practicing in the art. It is not intended to deny a limit to the invention to the exact construction or operation shown, nor to the apparatus described, and accordingly, suitable modifications to both the apparatus and the method is contemplated within the scope of the invention. I do, however, prefer that the inside diameter of the nozzle be at least 40 mm; the aggregate area of the orifices in the nozzle 30 be around 1250 square milllmetres;
and the nozzle length that disposes the orifices (30'') be about 350 mm. The angle of the tip or cone 30' of the orifice thereof should be inclined at approximately 45. In such application the water pressure preferrably ranges between 200 to 400 KPa. and the volume of water consumed will be in the order of 30 litres per second. Pressure ranges from 0 to 700 ~Pa. may be used.
For those skilled and practicing in the art the attached graphs 1 through 7 will be of value in understanding the utility of the invention.
Graph 1 depicts total settlement in centimetres against time after jetting in days under two conditions, the porous nozzle of the type disclosed in this invention, and a full open probe having no aperture. In other words the full opening probe is one whose cross-sectional area or orifice is identical in size to that internal diameter of the hose or conduit feeding the water to it. You will note that more settlement is achieved with the porous nozzle of the invention.
Graph 2 is similar to that of graph 1 except it depicts settlement after a given amount of days as a function of energy emitted by the nozzle. Note that in all cases the majority of the settlement occurs within two days.
Graph 3 plots water jetting force in newtons of the agreggate area of the openings of the orifices 0 as against a cross-sectional area of the hose. You will see that the idealized condition is very close to a ratio .5:1 -that is where maximum energy i8 emitted to the soil.
This is ~hown a second time, with more plotting points, in graph 7.
Graph 4 is a plot of the degree of compaction as a percentage over the energy applied over a given elapsed period of time from 10 days to 10 months as shown.
Graph 5, which is analogous to that of graph 1 and shows the degree of compaction over time plotting the full probe opening and the porous nozzle of the invention. Note that higher degree of compaction is achieved, and more immediately, with the nozzle of the invention.
Graph 6 also plots the porous nozzle of the invention as against the full probe opening on a graph showing vane shear in Kilo Pascals over a lapsed period of time after jetting. Note that a stronger backfill is obtained with the nozzle of the invention.
TO lAL SETTLEMENT, cm o o ~ r~ ~-~ ~
r _ ~ Z r -~t --113~70 TOTAL SETTLEMENT, cm ~ a o ` ~
, ,, 7(1 ~ t l l --t ~ t~
640 ~ ~~~ ~ h- âm 560- _ /
1 E1,--~ Lh: 25m _ 480- / ~
320 ¦ I ~ j \ Lh ~ 70 m / Lll- 100 m ~, 24 0 - ~
~: .
C~ _ Lh: LENGTH OF HOSE - _ O ~ t I I 1- t 1-(AREA OF OPENING) / (AREA GF HOSE) r~r~lnl '70 DEGREE OF COMPACTION %
o ~ ) Cl) r ~ 0 c~
o I I ~ I i. _ I I l l I
s ~0 DEGREE OF CCMPACTION %
a~ o ~ ~ ~ co O ._ . . . ~ t I . I
Q- ~ ~
I ~ I I ~ ~ I- I I
i? l VANE SHEAR, KPa ~ o ~ O
O I I I t ~-O
640 ~ \
/ ~;- 8m s60! ,~
t ' ~ Lh: 25m ,_ ~
3 160 Lh: 100~
--~ Lh:LENGTH OF HOSE ~' ) O l l ~ l ~ l (AREA OF OPENING)/(AREA OF HOSE) (~rar)h 7 ~3
--~ Lh:LENGTH OF HOSE ~' ) O l l ~ l ~ l (AREA OF OPENING)/(AREA OF HOSE) (~rar)h 7 ~3
Claims (11)
1. An apparatus for injecting, systematically, into soil, water whereby the adjacent soil is compacted with the aid of hydraulic forces, the apparatus comprising:
(a) a single hollow conical member defining a hollow interior extending into a cylindrical member as an extension thereof, each member defining a plurality of apertures in its wall that communicate the hollow interior to its exterior;
(b) a source of water supply;
(c) a flexible conduit interconnecting and communicating with the hollow interior and with the water supply; and, (d) control means for flowing water from the supply into the hollow member and out the plurality of orifices.
(a) a single hollow conical member defining a hollow interior extending into a cylindrical member as an extension thereof, each member defining a plurality of apertures in its wall that communicate the hollow interior to its exterior;
(b) a source of water supply;
(c) a flexible conduit interconnecting and communicating with the hollow interior and with the water supply; and, (d) control means for flowing water from the supply into the hollow member and out the plurality of orifices.
2. The apparatus as claimed in claim 1 wherein the conduit includes means for keeping the flow of water eminating from the apertures, within a predetermined range of pressures.
3. The apparatus as claimed in claim 2 wherein the said pressure means keeps the pressure in the range of between 0 and 700 KPa..
4. The apparatus as claimed in claim 2 wherein the said pressure means keeps the pressure in the range of between 200 to 400 KPa..
5. A method of compacting soil comprising the steps of:
(a) applying to a point source, a flow of water, and to the point source, a downward force, whereby, as result of the flow of water, and the weight, the point source tends to traverse into the depth of the ground;
(b) terminating at a prescribed depth the downward force and hence further penetration of the point source;
(c) applying thereto an upward force, whereby, under the continous flow of the water out of the point source it slowly migrates upward to rise to the surface causing the soil adjacent thereto to be inundated with water whereby, the soil is compacted by hydraulic forces.
(a) applying to a point source, a flow of water, and to the point source, a downward force, whereby, as result of the flow of water, and the weight, the point source tends to traverse into the depth of the ground;
(b) terminating at a prescribed depth the downward force and hence further penetration of the point source;
(c) applying thereto an upward force, whereby, under the continous flow of the water out of the point source it slowly migrates upward to rise to the surface causing the soil adjacent thereto to be inundated with water whereby, the soil is compacted by hydraulic forces.
6. A method of compacting soil comprising the steps of:
(a) applying to a first location, a point source, a flow of water and to the point source, weight, whereby, as a result of the flow of water, and the weight, the point source tends to traverse into the depth of the ground;
(b) terminating at a prescribed depth the penetration of the point source by applying thereto an upward force whereby, under the further continuous flow of the water, out of the point source and under the influence, as well, of the upward force;
(c) slowly migrating the point source to the surface causing the adjacent soil thereto to be inundated with water, whereby, the soil is compacted by hydraulic forces;
(d) repeating steps (a) through (c) at an adjacent location until the entire soil mass between said locations is completely saturated with water;
(e) draining the injected water from the saturated soil; then, (f) backfilling the upper surface region of the trench between said locations.
(a) applying to a first location, a point source, a flow of water and to the point source, weight, whereby, as a result of the flow of water, and the weight, the point source tends to traverse into the depth of the ground;
(b) terminating at a prescribed depth the penetration of the point source by applying thereto an upward force whereby, under the further continuous flow of the water, out of the point source and under the influence, as well, of the upward force;
(c) slowly migrating the point source to the surface causing the adjacent soil thereto to be inundated with water, whereby, the soil is compacted by hydraulic forces;
(d) repeating steps (a) through (c) at an adjacent location until the entire soil mass between said locations is completely saturated with water;
(e) draining the injected water from the saturated soil; then, (f) backfilling the upper surface region of the trench between said locations.
7. The method as claimed in claim 5 including all steps, successively, at further adjacent locations along a trench length so as to completely saturate the entire extent of the trench.
8. The method as claimed in claim 7 including the additional step of compacting the upper surface of the trench after backfilling.
9. The method as claimed in claim 5, 7 or 8 wherein the applying step (a) includes applying of valve water at a predetermined pressure less than 700 KPa..
10. The method as claimed in claim 5, 6 or 7 wherein the applying step (a) applies the water at a pressure in the range of 200 to 400 KPa..
11. The method as claimed in claim 5 or 6 including draining said water from the soil into the manhole by means of one or more openings, 100 mm to 200 mm in diameter, said openings to be made into the side of the manhole at the same invert of the upstream pipe.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000357176A CA1136870A (en) | 1980-07-28 | 1980-07-28 | Hydraulic method of soil compaction and apparatus therefore |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000357176A CA1136870A (en) | 1980-07-28 | 1980-07-28 | Hydraulic method of soil compaction and apparatus therefore |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1136870A true CA1136870A (en) | 1982-12-07 |
Family
ID=4117525
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000357176A Expired CA1136870A (en) | 1980-07-28 | 1980-07-28 | Hydraulic method of soil compaction and apparatus therefore |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1136870A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2072686A2 (en) * | 2007-12-21 | 2009-06-24 | Gualtiero Cenni | System and method for consolidating a building foundation soil |
| CN110469289A (en) * | 2019-08-20 | 2019-11-19 | 天津市水利勘测设计院 | Envelope equipment is filled out in a kind of drilling |
-
1980
- 1980-07-28 CA CA000357176A patent/CA1136870A/en not_active Expired
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2072686A2 (en) * | 2007-12-21 | 2009-06-24 | Gualtiero Cenni | System and method for consolidating a building foundation soil |
| EP2072686A3 (en) * | 2007-12-21 | 2012-05-23 | Gualtiero Cenni | System and method for consolidating a building foundation soil |
| CN110469289A (en) * | 2019-08-20 | 2019-11-19 | 天津市水利勘测设计院 | Envelope equipment is filled out in a kind of drilling |
| CN110469289B (en) * | 2019-08-20 | 2023-10-13 | 天津市水务规划勘测设计有限公司 | Drilling and filling and sealing equipment |
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