Patent Publication Number: US-2003235472-A1

Title: Packing apparatus for pressure type soil-nailing and soil-nailing construction method using the packing apparatus

Description:
FIELD OF INVENTION  
       [0001] The present invention relates to a packing apparatus for pressure type soil-nailing and soil-nailing construction method using the packing apparatus. More specifically, the invention relates to a packing apparatus for pressure type soil-nailing and soil-nailing construction method using the packing apparatus which is suitable for sealing closely grouting area which is formed in a bored hole and improving construction efficiency through grouting by pressure, that is, filling pressuringly of liquid grout.  
       BACKGROUND OF INVENTION  
       [0002] Generally, according to industrial development, it is unavoidable situation to develop a steep slope district such as a mountain district by production of housing complex or construction of new city, etc.  
       [0003] Accordingly, it is required to provide a construction method for slope stability that can satisfy construction efficiency, economical efficiency and preservation efficiency of environment as well as heighten an availability of land and secure stability and amenities of residing complex.  
       [0004] Soil-nailing which has been used most widely as a construction method for slope stability is a construction method which reinforces the ground and is utilized widely in Europe and United States of America with a purpose of slope reinforcement a soft timbering to dug surface and so on.  
       [0005] Such soil-nailing construction method is a construction method that augments a whole shearing strength of original ground oneself and prohibits a displacement of the ground within the limits of the possibility which is expected during construction or after completion of construction by inserting a nail in original ground to comparatively dense space without prestressing.  
       [0006] Especially, in the case of a replacement construction of dug site, when compared with other constructing method such as a heavy weight of concrete wall, a big pile wall and a slurry wall which places at a spot, etc., soil-nailing construction method has the advantage of inexpensive construction cost, a light weight of construction equipment and adaptation and flexibility of a spot and a ground condition, etc. and has a characteristic that can have enough resistibility without excessive displacement in case of even a dynamic load of earthquake, etc.  
       [0007] Conventional soil-nailing construction method is done in the order of digging of the ground, establishment of nail, placing of shot-crete, digging etc. and is as follows if explain referring to FIGS. 1 a - 1   d  and FIG. 2.  
       [0008] First, as illustrated to FIG. 1 a,  dig the ground to a stable height in which slope or wall  1  of pit digging is capable of self-support.  
       [0009] That is, ground digging for establishing a slope protection and a stiffener is basically the same as general ground digging.  
       [0010] However, because the dug surface of soil-nailing is used in many cases as the main structure, it needs to dig into correct position and shape. Also, according to the nature of the soil, it needs to dig by considering an dug depth in which the ground is capable of self-support, a curing time for injected grout or shot-crete to obtain a predetermined intensity and the like.  
       [0011] Maximum dug depth is generally related with apparent cohesion of the ground, it is good to limit to 2 m to the maximum for perpendicular digging of step by step.  
       [0012] Next, as illustrated to FIG. 1 b,  for establishing the stiffener, bore wall  1  and establish the nail  3  at a bored hole.  
       [0013] This time, said boring is done by a rock drill or a boring machine etc. and most of said boring use fluid. (air, water, cement grout and bentonite)  
       [0014] Ordinarily, a deformed bar or a steel bar etc. can be used as the nail  3  which is used at the soil-nailing construction method and noxious earth or oil etc. of portions which are attached to grout should be removed beforehand.  
       [0015] The nail  3  that is used for permanent structures should consider an extra for rust when designed or use steel materials in which rust prevention is processed, and it is good that said nail  3  uses without a joint, however, in case that said nail should be obliged to connect because insertion length thereof is long, a coupler should be used and connection by general welding should be avoided.  
       [0016] At insertion of the nail  3 , in order to secure the minimum thickness of grout, it is good to use interval materials so that the nail  3  may be situated at center of the boring hole.  
       [0017] Next, as illustrated to FIG. 1 c,  if shot-crete is cured after placing, execute ground digging again, as showed to FIG. 1 d.    
       [0018] In the meantime, process to establish the nail  3  at the bored hole is as follows.  
       [0019] First, after inserting the nail  3  to said bored hole  11 , grout cement milk (do not illustrate) into a hole by no pressure.  
       [0020] Next, establish a wire mesh  13  to said wall  1  and arrange a reinforcing bar  15  to crosswise on said wire mesh  13 .  
       [0021] Next, after fixing pressurizingly said reinforcing bar  15  with a plate  17  and a nut  19  that is fastened to said nail  3 , place shot-crete toward said wall.  
       [0022] This time, said grouting should fill completely interior of the bored hole  11  and should be executed repeatedly 3˜6 times according to a tendency that liquid grout is permeated in surrounding the ground.  
       [0023] However, because such conventional soil-nailing construction method adapts gravity type grouting, solidifying time is long and grouting should be repeated about 3˜6 times in order to supplement contraction phenomenon.  
       [0024] Thereby, because conventional soil-nailing construction method prolongs the process, construction efficiency is depreciated, thus there was a problem that construction period becomes longer.  
       [0025] Also, because the bored hole is slanted downwardly, it is impossible to fill liquid grout in grouting area, a gap between the boring hole and the ground is produced, whereby there was a problem to provoke a fatal defect at ground reinforcements.  
       SUMMARY OF INVENTION  
       [0026] The present invention is proposed in order to solve the above-described problems. An object of the present invention is to provide a packing apparatus for pressure type soil-nailing and soil-nailing construction method using the packing apparatus which can shorten a construction term and improve construction efficiency by executing grouting at a situation which seals completely grouting area by injecting a quick forming expansion agent at the packing apparatus.  
       [0027] Another purpose of the present invention is provide to the packing apparatus for pressure type soil-nailing and soil-nailing construction method using the packing apparatus which is suitable for improving stability of ground reinforcements by filling liquid grout to even a gap between the boring hole and the ground and void of the ground through pressure type soil-nailing.  
       [0028] In order to achieve the above objects, a packing apparatus for pressure type soil-nailing according to the present is characterized by comprising, in a packing apparatus for sealing a grouting area by being inserted at a hole that is bored on an dug surface, a nail; a first packing and a second packing that are fitted at a predetermined interval mutually at to the lengthwise direction of said nail; a non-woven fabric for sealing space between the first packing and the second packing by providing to wrap the circumferential surface of said first packing and second packing; a first grouting pipe for injecting liquid grout in said grouting area, the first grouting pipe pierces said first packing and second packing but one end of the pipe is established in a position near from one end of said nail; a discharging pipe of air and foreign material for discharging air and foreign material of a grouting area by said grouting, the discharging pipe of air and foreign material pierces said first packing and second packing but one end of the pipe is established in a position near from of said second packing; and a foaming urethane injection pipe for injecting a foaming urethane of which bulk is expanded by being gel at space that is sealed by said non-woven fabric, the foaming urethane injection pipe pierces said first packing but one end of the pipe is established at space between said first packing and second packing.  
       [0029] Here, it is desirable that said packing apparatus for pressure type soil-nailing further comprises a second grouting pipe for injecting liquid grout into said grouting area by piercing said first packing and second packing but establishing the end thereof at a position near from said second packing, and further comprises wire rings for combining closely said non-woven fabric on the circumferential surface of said first and second packing by screwing, said wire rings are established at outside of said non-woven fabric along the circumferential surface of said first and second packing in order to combine said first, second packing and said non-woven fabric.  
       [0030] In the meantime, soil-nailing construction method using a packing apparatus for pressure type soil-nailing of the present invention is characterized by comprising digging the ground to a stable height in which slope or wall of pit digging is capable of self-support; forming a boring hole by boring a hole of a predetermined diameter at a proper position of said dug ground; establishing by inserting at the boring hole said packing apparatus for pressure type soil-nailing with which a nail is established; forming isolated grouting area for injecting liquid grout by contacting closely said packing apparatus for pressure type soil-nailing at a inner diameter of the boring hole; filling by injecting liquid grout in said grouting area; discharging to outside air and foreign material in grouting area when liquid grout is injected in said grouting area; sealing said grouting area by blocking a passage in which said air and foreign material are discharged; and filling pressurizingly liquid grout in said grouting area so that liquid grout may fill up to even void and joint of the ground surrounding boring hole.  
       [0031] Here, soil-nailing construction method further comprises injecting liquid grout again after passing a predetermined time since completion of step to fill pressurizingly liquid grout in said grouting area. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0032] Further objects and advantages of the invention can be more fully understood from the following detailed description taken in conjunction with the accompanying drawings, in which:  
     [0033]FIGS. 1 a - 1   d  are flowcharts of construction for explaining a soil-nailing construction method according to the prior art.  
     [0034]FIG. 2 is a conceptual view showing an embodiment to establish a nail according to conventional soil-nailing construction method.  
     [0035]FIG. 3 is a perspective view of the packing apparatus for pressure type soil-nailing of the present invention.  
     [0036]FIG. 4 is a perspective view with parts taken away of the packing apparatus for pressure type soil-nailing of the present invention.  
     [0037]FIG. 5 is a cross section of the ground for explaining the establishment state of the packing apparatus for pressure type soil-nailing of the present invention.  
     [0038]FIG. 6 is a flowchart illustrating step-by-step soil-nailing construction method using the packing apparatus of the present invention.  
    
    
     BEST MODE FOR IMPLEMENTING THE INVENTION  
     [0039] Below, the packing apparatus for pressure type soil-nailing of the present invention as described above will be explained in detail with reference to the accompanying drawings.  
     [0040]FIG. 3 is a perspective view of the packing apparatus for pressure type soil-nailing of the present invention, FIG. 4 is a perspective view with parts taken away of the packing apparatus for pressure type soil-nailing of the present invention, and FIG. 5 is a cross section of the ground for explaining the establishment state of the packing apparatus for pressure type soil-nailing of the present invention.  
     [0041] As illustrated to drawings, at the packing apparatus for pressure type soil-nailing of the present invention are inserted the first packing  33   a  and the second packing  33   b  at a predetermined interval mutually to a lengthwise direction of the nail  31  in which screw threads are formed on the circumferential surface.  
     [0042] Also, at the packing apparatus for pressure type soil-nailing of the present invention is established non-woven fabric  35  that seals empty space between said first packing  33   a  and second packing  33   b  by wrapping the circumferential surface of said first packing  33   a  and second packing  33   b.    
     [0043] Instead of said non-woven fabric  35 , nylon or tent fabric, etc. can be used and it does not matter if any material that has enough resistibility to pressure according to bulk swelling of foaming urethane to be injected into empty space between said first packing  33   a  and second packing  33   b.    
     [0044] Also, as the material of said first packing  33   a  and second packing  33   b,  rubber, soft plastic, wood, steel plate, etc. can be used and rubber of the materials is most desirable.  
     [0045] That is, in case of using the packing of rubber quality, more close unity is possible between a grouting pipe, a discharging pipe of air and a foreign material, or a foaming urethane injection pipe and so on and a packing that will be explained more in detail in below.  
     [0046] Also, at the packing apparatus for pressure type soil-nailing of the present invention, the first grouting pipe  37  is established which pierces said first packing  33   a  and second packing  33   b  and firstly injects liquid grout in said grouting area, and the discharging pipe  39  of air and foreign material is established which pierces said first packing  33   a  and second packing  33   b  and discharges air and foreign material of grouting area due to said grouting.  
     [0047] It is desirable that one end of said first grouting pipe  37  is established at a longitudinal end of said boring hole, that is, near one end of said nail  31 , and it is also desirable that one end of said discharging pipe  39  of air and foreign material is established near said second packing  33   b.    
     [0048] For reference, due to injecting of liquid grout, said discharging pipe  39  of air and foreign material does so that pressure can be applied in said grouting area by closing the inlet after discharging air or foreign material as well as discharging to outside of the boring hole foreign materials such as air or water which occurs in said grouting area.  
     [0049] If pressure is applied in said grouting area, as said liquid grout is filled closely to even void and joint that is formed at the ground around the boring hole by said pressure while said liquid grout is solidified, whole stability of soil nail can be improved.  
     [0050] Also, the packing apparatus for pressure type soil-nailing of the present invention is established so that foaming urethane injection pipe  43  for injecting a quick forming expansion agent such as foaming urethane at space which is sealed by said non-woven fabric  35  may pierce said first packing  33   a.    
     [0051] One end of said foaming urethane injection pipe  43  is situated at space between said first packing  33   a  and second packing  33   b.    
     [0052] Said foaming urethane becomes gel by injecting liquid urethane in the state in which nail  31  is established and said liquid urethane becomes gel at space between said first packing  33   a  and second packing  33   b , thereby the bulk swells.  
     [0053] Generally, liquid urethane has an advantage that can regulate very variously all sorts of material properties such as foaming magnification and mechanical strength, etc. Because the time in which liquid urethane becomes gel is actually no more than a few minutes, in case of filling this to space which is sealed by non-woven fabric  35 , the first liquid grout can be injected in a little while.  
     [0054] In order to combine said non-woven fabric  35  and said first and second packing  33   a ,  33   b , wire rings  45  are established on outside of said non-woven fabric  35  along the circumferential surface of said first and second packing  33   a ,  33   b.    
     [0055] As said wire rings  45  unite closely said non-woven fabric  35  with the circumferential surface of said first and second packing  33   a ,  33   b  by screw fastening, liquid urethane is injected into non-woven fabric  35 , thus even if the bulk swells, more strong support is possible.  
     [0056] Additionally, the packing apparatus for pressure type soil-nailing of the present invention further comprises a second grouting pipe  41 .  
     [0057] Said second grouting pipe  41  pierces said first packing  33   a  and second packing  33   b  but is established so that the one end thereof may approximate to said second packing  33   b.    
     [0058] Such second grouting pipe  41  is a pipe for injecting the second liquid grout in order to fill empty space that occurs at interior of boring hole by dry shrinkage of cement after the first grouting.  
     [0059] Said second grouting pipe  41  fills liquid grouts secondly by a pressure method to space in which the first liquid grout does not to fill, whereby close filling can be done over a whole grouting area, and at the same time it does so that liquid grout can be filled sufficiently to even void that is formed on the ground around the boring hole.  
     [0060] Below, soil-nailing construction method using the packing apparatus of the present invention will explain to step-by-step referring to FIG. 6. However, explain one embodiment in main a use of the packing apparatus for pressure type soil-nailing of the present invention.  
     [0061] Soil-nailing construction method using the packing apparatus of the present invention comprises step to dig the ground (S 101 ), step to form the boring hole (S 102 ), step to establish the packing apparatus for pressure type soil-nailing (S 103 ), step to form isolated grouting area (S 104 ), step to fill liquid grout (S 105 ), step to discharge air and foreign material (S 106 ), step to seal grouting area (S 107 ) and step to fill pressurizingly liquid grout (S 108 ).  
     [0062] If explain in detail such soil-nailing construction method of the present invention, first, step (S 101 ) is executed to dig the ground to a stable height in which slope or wall of pit digging is capable of self-support.  
     [0063] Next, step (S 102 ) is executed to form the boring hole by boring a hole of a predetermined diameter in a proper position of said dug ground.  
     [0064] Next, step (S 103 ) is executed to establish by inserting the packing apparatus for pressure type soil-nailing in which the nail  31  such as showed in FIG. 3 is established at the bored hole of said dug ground.  
     [0065] Next, step (S 104 ) is executed to form isolated grouting area by closely contacting said packing apparatus for pressure type soil-nailing at diameter of the boring hole.  
     [0066] For this, inject a quick forming expansion agent such as liquid urethane at space between the first packing  33   a  and the second packing  33   b  that are sealed by said non-woven fabric  35  through said foaming urethane injection pipe  43 .  
     [0067] As described above, since said liquid urethane becomes gel very fast, if passing several minutes after injecting, it becomes gel, whereby the bulk swells.  
     [0068] This time, because non-woven fabric  35  is expanded, said non-woven fabric  35  closely contacts with inner diameter of the boring hole.  
     [0069] Herewith, isolated grouting area that can inject liquid grout is formed at interior of said boring hole.  
     [0070] Next, step (S 105 ) is executed to fill by injecting in grouting area liquid grout such as cement milk.  
     [0071] For this, inject liquid grout in isolated grouting area through said first grouting pipe  37 .  
     [0072] In order that said liquid grout is filled smoothly in said grouting area, air or foreign material etc. in said grouting area should be discharged to outside.  
     [0073] Accordingly, step (S 106 ) is executed to discharges air or foreign material etc. to outside through the discharging pipe  39  of air and foreign material, at the same time liquid grout is filled in grouting area.  
     [0074] Next, step (S 107 ) to seal grouting area by blocking a discharge passage of air and foreign material is executed.  
     [0075] For this, the discharging pipe  39  of air and foreign material that did the function of the passage in which said air and foreign material is exhausted is to be closed.  
     [0076] Next, step (S 108 ) to fill pressurizingly liquid grout in said grouting area by continuing to inject liquid grout is executed.  
     [0077] By filling pressurizingly of such liquid grout, liquid grout is filled to even void and joint that is formed in the ground surrounding the boring hole.  
     [0078] If a predetermined time passes after step (S 108 ) to fill pressurizingly liquid grout is completed, step to inject again liquid grout can be further included.  
     [0079] If tens of minutes pass after filling of liquid grout in said grouting area is completed, dry shrinkage occurs while filled liquid grout, that is, cement milk is solidified and due to this, empty space exists at surrounding said second packing  33   b . In order to inject liquid grout to said empty space, additional injecting of liquid grout is required.  
     [0080] Because said second grouting pipe  41  is established so that one end thereof may approximate to said second packing  33   b , it can fill liquid grout more easily at surrounding said second packing  33   b  where due to dry contraction, the first liquid grout was not filled.  
     [0081] If characteristic steps of the present invention as mentioned above are executed, the finish work of construction can then be carried out.  
     [0082] For example, step to establish a wire mesh at wall of the ground is executed.  
     [0083] Next, after arranging a reinforcing bar to crosswise on said wire mesh, step is executed to fix pressurizingly said reinforcing bar with a plate and a nut that are fastened to said nail  31 .  
     [0084] Finally, as step to place shot-crete is executed, soil-nailing construction method using the packing apparatus for pressure type soil-nailing of the present invention is completed.  
     [0085] Although preferred embodiments of the present invention has been described, various modifications, variations and equivalents may be used for the present invention. Manifestly, the above embodiments of the present invention may be properly modified and applied equivalently. Accordingly, the above descriptions do not limit the scope of the present invention defined by means of the accompanying claims.  
     INDUSTRIAL AVAILABILITY  
     [0086] As described above, the packing apparatus for pressure type soil-nailing and soil-nailing construction method using the packing apparatus of the present invention has the following effects.  
     [0087] As grouting by pressurizing is progressed at the situation that seals firmly inner surface of the boring hole by using the packing apparatus that injected a quick forming expansion agent, grouting work can be done in a short time, thereby can shorten a construction time.  
     [0088] Also, because liquid grouting can be filled firmly to even void and joint that is formed at the ground through pressure type soil-nailing, stability of the ground reinforcements can be improved.