JP2002256790A - Method and device for filling drilled hole based on grout material injection via down-the-hole drill - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent backflow penetration of a grout material into a pile body (casing) by injecting and charging the grout material for fixing into a clearance between a drilled hole and the pile body in installation of a prevention pile into the drilled hole and to facilitate removal of a down-the-hole drill for safely and efficiently embedding the prevention pile at a low cost. SOLUTION: In excavation of the drilled hole 18 into the ground 5, the pile body (casing) 2 is arranged integrally on the outside of the down-the-hole drill 3, and to a compressed air feeding passage such as an air line and an air hose, the grout material 17 is injected to be charged only into a clearance part 19 between the compressed air feeding passage and the outer circumferential face of the grout material 17 such as cement milk while excavation is carried out to a predetermined depth by means of a bit 6. The upper end part of the pile body (casing) 2 is sealed by means of a plate 14. In this way, the grout material 17, the air, or the like is prevented from reversely flowing into the inside, and in the following construction step, the down-the-hole drill 3 can be pulled out smoothly.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The disclosed technology relates to a method of directly driving a pile body for prevention of landslides into an alternate layer of a soft ground layer and a hard ground layer (for example, a rock bed) in a landslide prevention construction or the like. Belonging to the technical field.

[0002]

2. Description of the Related Art There is a technique in which a tubular pile body (casing) such as a deterrent pile for preventing landslide such as a steel pipe pile or a concrete pile is cast on a target ground including a hard ground and a bedrock layer.

[0003]

However, the above-mentioned technique involves a full-rotation type all-casing excavator or the like, but in this technique, the advance excavation step and the pile-in step are separated. However, there is a disadvantage that the process is complicated, and it is difficult to shorten the construction period.

Further, a step of injecting and filling grout to fix the excavated vertical hole wall (drilled hole) and the pile body rotationally press-fitted into the excavated hole is required.
Although the technique is performed by pumping or the like, there is a disadvantage that the process is significantly restricted and the cost is increased as a result, and there is a disadvantage that accuracy is poor.

[0005] At this time, if the grout to be injected and filled is insufficient, there is a problem that accuracy is deteriorated, and there is a problem that the reliability of post-construction is reduced. Therefore, the grout to be injected and filled needs to be tight. However, the filling and filling of the grout is performed by a high-pressure pump, so that the grout in the middle of the pressure feeding flows back to the pump, resulting in poor accuracy.Therefore, there is a problem that the grout injection and filling must be repeatedly performed through the pump again. there were.

[0006]

SUMMARY OF THE INVENTION An object of the invention of this application is to solve the problem of grout that is injected and filled in a gap between a pile body built in a borehole and a borehole based on the above-mentioned prior art,
Using a down-the-hole drill for the drilling instead of prior drilling, a pipe group is arranged outside the down-the-hole drill, and a grout material is tightly sealed only between the pipe group and the drill hole or both in a sheath shape. So that
It is an object of the present invention to provide a method and an apparatus for driving a pile body through grout injection into a hard ground which is advantageous for the field of civil engineering in the construction industry.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the construction of the invention of the present application, in which the above-mentioned objects are summarized in the above-mentioned object, is performed by drilling a hard ground with a down-the-hole drill. In the method of injecting and filling a material, the grout material is fed through a supply path of compressed air, which is a driving force of the down-the-hole drill, as a first backbone. By supplying compressed air at the same time, it is possible to assist the pumping force of the grout material,
Also, a pipe group is attached to the outer periphery of the down-the-hole drill so that the pipe group can be erected in the hole at the same time as the hole drilling operation. Using a down-the-hole drill that can be freely projected and expanded or contracted and swiveled, and arranging a group of pipes outside the down-the-hole drill to simultaneously drill holes and embed the group of pipes When the grout material is injected and filled into the gap between the down-the-hole drill and the hole wall via the outer peripheral surface of the pipe group after reaching the target depth, the bit of the down-the-hole drill is fixed inside the pipe group. Or in a predetermined discharge state, or make a protruding swivel, and close the upper end or lower end of the pipe group or fill the pipe by filling the pipe with filler. As a result, the grout material is prevented from flowing into the circular cross-section of the tubular pile body and the down-the-hole drill, and the grout material is injected and filled into the ring-shaped gap between the outer peripheral surface of the tubular pile body and the hole wall. If the grout material is injected and filled further, inside and outside the pipe group,
The properties of the upper and lower layers and the like are also made different from the outside, so that in the pile driving device for the hard ground, after reaching the drilling target depth, the gap between the outer peripheral surface of the tubular pile body and the drill hole wall is formed. In an apparatus for injecting and filling a grout material, the inflow of grout material into a circular cross section of the tubular pile at the upper end or the lower end of the tubular pile and the down-the-hole drill is suppressed, and the outer peripheral surface of the tubular pile and a hole hole hole are formed. The second core is to allow the pile circumference fixing material to be freely fed into the ring-shaped gap of the above, and additionally, a sealing device is provided above the tubular pile body projecting from the ground surface after reaching the target drilling depth. And technical measures taken

[0008]

In the above-described configuration, when placing deterrent piles for preventing landslides on the soft ground layer and the hard ground layer, a pipe group is provided on the down-the-hole drill, and the down-the-hole drill is used. The drilling is performed, and at the same time, when the down-the-hole drill reaches a predetermined depth or is lifted from the middle thereof, grout is performed from a compressed air supply passage such as an air line or an air hose to an air ejection port of a bit of the down-the-hole drill. The grout is fed from the bit into the gap between the drilled hole and the pile, and the grout is injected and filled. At this time, a plate is disposed at the top or bottom of the pile, or the inside of the pile is filled with water or the like. The pipe group is saturated to prevent the grout material rising from below from entering the casing of the down-the-hole drill due to backflow. Or only between the drilling through the pile body, it is obtained as the injection filling of grout or the like of different properties to such upper and lower layers in and out of the pipe groups can be reliably provided in the sheath shape.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following is a description of embodiments of the present invention as embodiments of the present invention, with reference to the accompanying drawings.

In FIG. 1, reference numeral 1 is a schematic diagram of a system according to the invention of the present application, in which a pile body 2 to be driven is a deterrent pile, and a down-the-hole for drilling is provided inside the pile body (casing) 2. Some gaps 4 have been corrected to facilitate insertion and extraction between the drill 3 and the pile 2 (casing) 2.

In order to excavate the ground 5 such as soft ground or hard ground alternately to a predetermined depth, a down-hole drilling bit 3 such as a shutter of a camera as shown in FIG. It is arranged at the tip of the shaft 7 so that it is enlarged during excavation and reduced during extraction.

The shaft 7 has a bit 6 at the tip as shown in FIGS. 3 and 4, and the bit 6 is provided with an air ejection port 8 and communicates with the air ejection port 8. Although not shown, a compressed air supply passage such as an air line or an air hose is connected to a predetermined swivel joint or the like.

A shaft-like rod 10 having a joint 9 as a connecting portion is connected to the upper stage of the shaft 7 via a bolt screw 12 for connecting a hydraulic cylinder 11 to the rod 10. And band 13
A plate 14 is provided on the upper part of the hydraulic cylinder 11 with a sealing rubber 15 and the like, and is fixed so as to be in close contact with the pile body 4 from above, as shown in FIG. In the center, a hole 16 through which the rod 10 is inserted is formed.

The supply of hydraulic oil to the hydraulic cylinder 11 is performed by a hydraulic unit (not shown), and is constituted by an independent power system so that the hydraulic cylinder 11 can be operated as required in operation.

The upper connection of the pile body (casing) 2 to a predetermined depth is adapted to be connected to a joint (not shown) as an adapter of the rod 10.

Incidentally, the inside of the deterrent pile 2 is sealed so as to prevent leakage of the filler water or the like as a saturating material.

In the above structure, the band 13 is tightened against the restraining pile 2, the upper end of the hydraulic cylinder 11 is connected to the plate 14 which is in close contact with the restraining pile 2, and the rubber seal 15 is applied thereto, and the state of the pile body (casing) 2 is obtained. The inside of the tightly sealed and sealed pile (casing) 2 is sealed, and a grind material 17 such as cement milk filled through an air injection and supply passage is drilled by a bit 6 with a drilled hole 18 and the pile (casing). 2), which is lifted from below only into the gap 19 and injected and filled, so that the pile body (casing) 2 is prevented from flowing backward and entering.

The hydraulic cylinder 11 and the plate 14 are drilled in the alternation ground 5 between the soft ground and the rock by using the system 1 in which the pile 1 is set at a predetermined position.

While drilling and forming a drilled hole 18 at a predetermined depth in the pile body (casing) 2, the pile body (casing) of the restraining pile is formed.
When penetrating, inserting, and placing 2, the bit 6 is expanded to excavate the hard ground in the same manner as in the conventional manner, and at the same time, the grout material 17 such as cement milk is supplied from the air ejection port 8 to the hydraulic pump or swivel joint. The high-pressure air is fed simultaneously with the high-pressure air, and when the air is blown out from the air blowing port 8, the grout material 17 of the fed cement milk is blown out with the help of the compressed air to form a hole formed as shown by an arrow in FIG. The gap 19 between the pile body (casing) 2 and the grout material 17 such as compressed air or cement milk, which is surely injected and filled by raising the gap 19 between the pile body (casing) 2 and assists the filling, is down-the-hole drilled in the pile body (casing) 2. 3 does not flow backward between the shafts 7, and as a result, the grout material is injected and filled only as designed between the pile body (casing) 2 and the drill hole 18. Ri, raising the down-the-hole drill 3 bit 6 pile body by scaled down (casing) 2 from within the set depth.

In FIG. 1, reference numeral 20 denotes an air layer interposed between the pile body (casing) 2 and the shaft 7 of the down-the-hole drill 3 therein.

Next, a more specific embodiment will be described with reference to FIGS.

In the embodiment shown in FIGS.
The drill 3 is drilled to a predetermined depth by the bit 6 of the drill 6 and the grout pressure is fed from the pumping device 20 to the grout material 17 through the air discharge passage 21 from the air ejection port 22 ′ of the bit 6 to the drill hole 18 and the down hole. It is ejected from the drill 3 toward the upstream and injected and filled as described above.

The embodiment shown in FIGS. 9 and 10 is similar to the embodiment shown in FIGS.
In addition, the air pressure feeding and feeding device 22 is added to and assisted by adding high pressure air 23 to the grout material 17.

In the embodiment shown in FIGS. 11 and 12, a pipe group 24 is arranged outside the down-the-hole drill 3 to form a blocking wall between the hole 18 and the down-the-hole drill 3, and the bit of the down-the-hole drill is formed. 6 is advanced beyond the tip of the group of circulating pipes 24 so that the grout material 17 is cut out from the air ejection port 21 of the bit 6 through the air outlet port 21 of the bit 6. In the embodiment shown in FIGS. 13 and 14, the grout material 17 is injected and filled in the drilled hole 18 in the pipe group 24 of the bit 6 in the embodiment shown in FIGS. In the embodiment shown in FIGS. 15 and 16, the grout material 17 and the pipe group 24 are internally mounted while the shutter type bit 6 protrudes from the end of the pipe group 24 and is enlarged to perform turning excavation. Injected and filled into that boring 18.

The hole 18 is filled and injected.

The embodiment shown in FIGS. 17, 18 and 19 corresponds to claim 7, in which a ring-shaped closing body 25 is interposed between the bit 6 and the pipe group 24 so that The space inside the pipe group 24 is sealed by closing the space, and the pipe group 24 and the down-the-hole drill 3 are closed.
This is a form in which the grout material 17 is prevented from entering the inside.

Next, in the embodiment shown in FIG. 20 (g), the pipe group 24 is raised and lowered to an appropriate level while the bit 6 of the down-the-hole drill 3 is enlarged, and the grout material is formed outside the hole 18 and the pipe group 24. In this embodiment, a pile is formed as a structure by injecting and filling 17 and the pipe group 24 is removed after forming the pile 17 'as described above and forming a tubular pile as described above. In (i), only the pipe group 24 is removed while the down-the-hole drill 3 is pulled out to form a pile body in which the properties of the grout materials 17 ″ and 17 ″ inside and outside the pipe group 24 are different. In the embodiment shown in (b), when the pipe group 24 is removed, the properties of the inner grout 17 ″ and the outer grout 17 ″ are different. In a manner that You.

In addition to the above-described embodiments, a type in which the grout material 17 having a ring shape in cross section of the pipe group 24 is made different over the upper and lower layers, etc., is also possible.

In this manner, the pipe group 24 of the pile body (casing) 2 is built together with the down-the-hole drill 3 in the borehole 18, and the grout material 17 is reliably injected and filled between the borehole 18 and the pile 18. The standing posture of the body (casing) 2 is fixed, and the construction of the next adjacent deterrent pile is repeated.

The embodiment of the invention of this application is not limited to the above-mentioned embodiment, and for example, grout material can be simultaneously injected and filled simultaneously with excavation.

The target pile 2 is not limited to deterrent piles.
Various modes, such as a steel pipe pile and a concrete pile, can be adopted.

[0032] Then, in the deterrent pile which has been completed, the driving can be smoothly performed as designed without any residue of grout material such as cement milk inside, and the down-the-hole drill can be smoothly pulled out. It can be performed and the reliability for post-construction can be sufficiently secured.

When the hole 18 has a long depth, the down-the-hole drill 3 and the shaft 10 as an adapter can be connected and connected to a predetermined length through an appropriate joint. .

[0034]

According to the present invention, when a pile body (casing) such as a deterrent pile is driven into the ground, a drill body such as a deterrent pile is used for excavation of a borehole and installation of the pile body (casing) into the borehole. The casing is fixed stably to the drilled hole via cement grout such as cement milk. It can be fixed in a stable state at the same time, and the pile body is driven as designed. The effect is achieved.

When drilling the hole, the pile body (casing) is integrally held by the down-the-hole drill together with the drilling of the hole using the down-the-hole drill in the ground. The pile body (casing) can be built in the borehole, so the excavation and building can be performed in one process in one pass, and the excellent effect of shortening the construction period by shortening the process is achieved. .

After reaching a predetermined depth of the drilling,
Alternatively, a grout material such as cement milk or the like may be added to the grout material via a compressed air supply passage such as an attached air line or an air hose or a compressed air supply passage from the air ejection port of the bit on the way to the arrival. At the same time, the air to be supplied to the bit is simultaneously supplied and supplied, and both the supplied grout material and the air are sealed so that neither the backflow nor the inside of the pile body is performed. The pile body (casing) is filled by injecting and filling only into the ring-shaped gap and sealing at least the upper end and the lower end of the pile body (casing) so as not to flow backward into the pile body (casing). The grout material in the compressed air supply passage such as the internal air line and air hose does not enter, and the down-the-hole drill can lift and lower the pile body (casing) smoothly. It is achieved.

[0037] Therefore, an excellent effect that the pile body (casing) can be stably built into the drilled hole with time can be obtained. In addition, a grout material such as cement milk can be selectively supplied together with air using a compressed air supply passage such as an air line or an air hose of a down-the-hole drill. An excellent effect is achieved in that the embedding can be freely selected and a stable pile body (casing) can be driven into the borehole.

Further, at the time of embedding, at least the upper end of the upper end and the lower end of the pile body (casing) is sealed.
Grout material such as cement milk supplied through a compressed air supply passage such as an air line or an air hose to the bit of the down-the-hole drill does not flow backward into the pile (casing) being built, and lifts up. An excellent effect is obtained in that the pull-out can be performed smoothly when used in the next stage of the down-the-hole drill.

In the invention of the present application, the pile body (casing) is sealed by using only a device for sealing the upper end of the pile body (casing) so that the pile body is brought into close contact with the upper end direction of the pile body. In accordance with the length and depth of the scale, the position of each pile body (casing) to be connected can be shifted and fixed via a joint. Body (casing)
An excellent effect is obtained in that a system can be adopted in which a sealing body such as a plate at the upper end can be selectively set.

Since a pile body (casing) such as a deterrent pile can be securely fixed to a drilled hole, an excellent effect that the next stage can be performed with high reliability and high accuracy can be obtained.

Further, in the system unit, a bit type in which the tip bit can be enlarged and reduced simultaneously with the shutter of the camera which can be enlarged and reduced can be used, so that the construction cost is not particularly increased and the construction efficiency is reduced. In combination with the improvement, excellent effects such as high safety, low cost, and construction can be achieved.

Further, since a group of pipes can be arranged as a wall on the outer peripheral surface of the down-the-hole drill and grout materials having different properties can be injected and filled inside and outside thereof, the sectional state of the pile can be formed according to the situation. The excellent effect that can be performed is produced.

[Brief description of the drawings]

FIG. 1 is an overall schematic longitudinal side view of the system of the present invention.

FIG. 2 is a down-the-hole drill bit of FIG.
It is a plane sectional view.

FIG. 3 is a schematic perspective view of the structure of a down-the-hole drill.

FIG. 4 is a side surface view of a shaft of an adapter.

FIG. 5 is a schematic view of a band of a sealing plate;
(A) is a top view, (B) is a side view, and (C) is a bottom view.

FIG. 6 is a schematic view of a sealing plate, wherein (d) is a top view, (e) is a side view, and (f) is a bottom view.

FIG. 7 is a side view of the basic embodiment.

FIG. 8 is a plan sectional view of the bit.

FIG. 9 is a side view of one embodiment.

FIG. 10 is a plan sectional view of the bit.

FIG. 11 is a side view of a specific embodiment.

FIG. 12 is a plan sectional view of the bit.

FIG. 13 is a side view of another embodiment.

FIG. 14 is a plan sectional view of the same.

FIG. 15 is a side view of another embodiment.

FIG. 16 is a plan sectional view of the bit.

FIG. 17 is a side view of still another embodiment.

FIG. 18 is an enlarged plan sectional view of the bit.

FIG. 19 is an enlarged plan sectional view of the bit.

FIG. 20 is a side sectional view showing a relationship between a pile body and a grout material;
(G) is a side view of the connection between the pipe group and the pile, (H) is a cross-sectional side view of the pipe group withdrawal, (I) is a cross-sectional view of the filling of grout material inside and outside the pipe group, and (N) is the inside of the borehole. The double structure sectional view of the pile body of grout material.

[Explanation of symbols]

 3 Down the hole drill 2 Pile (casing) 6 Bit 5 Ground 17 Grout material 8 Air ejection port 19 Gap 14 Sealing device (plate) 24 Pipe group 25 Closure

[Procedure amendment]

[Submission date] December 25, 2001 (2001.12.
25)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0025

[Correction method] Change

[Correction contents]

The hole 18 is filled and injected.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0026

[Correction method] Change

[Correction contents]

The embodiment shown in FIGS. 17, 18 and 19 corresponds to claim 7, in which a ring-shaped closing body 25 is interposed between the bit 6 and the pipe group 24 so that The pipe group 24 and the down-the-hole drill 3 are sealed by closing the space of the pipe group 24.
This is a form in which the grout material 17 is prevented from penetrating into the inside. (However, FIGS. 16 and 18 have the same embodiment.)

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] Brief description of drawings

[Correction method] Change

[Correction contents]

[Brief description of the drawings]

FIG. 1 is an overall schematic longitudinal side view of the system of the present invention.

FIG. 2 is a down-the-hole drill bit II-II of FIG. 1;
It is a plane sectional view.

FIG. 3 is a schematic perspective view of the structure of a down-the-hole drill.

FIG. 4 is a side surface view of a shaft of an adapter.

FIG. 5 is a schematic view of a band of a sealing plate;
(A) is a top view, (B) is a side view, and (C) is a bottom view.

FIG. 6 is a schematic view of a sealing plate, wherein (d) is a top view, (e) is a side view, and (f) is a bottom view.

FIG. 7 is a side view of the basic embodiment.

FIG. 8 is a plan sectional view of the bit.

FIG. 9 is a side view of one embodiment.

FIG. 10 is a plan sectional view of the bit.

FIG. 11 is a side view of a specific embodiment.

FIG. 12 is a plan sectional view of the bit.

FIG. 13 is a side view of another embodiment.

FIG. 14 is a plan sectional view of the same.

FIG. 15 is a side view of another embodiment.

FIG. 16 is a plan sectional view of the bit.

FIG. 17 is a side view of still another embodiment.

FIG. 18 is an enlarged plan sectional view of the bit. (However, this is the same mode as FIG. 16.)

FIG. 19 is an enlarged plan sectional view of the bit.

FIG. 20 is a side sectional view showing a relationship between a pile body and a grout material;
(G) is a side view of the connection between the pipe group and the pile, (H) is a cross-sectional side view of the pipe group withdrawal, (I) is a cross-sectional view of the filling of grout material inside and outside the pipe group, and (N) is the inside of the borehole. The double structure sectional view of the pile body of grout material.

[Description of Signs] 3 Down the hole drill 2 Pile body (casing) 6 Bit 5 Ground 17 Grout material 8 Air ejection port 19 Gap 14 Sealing device (plate) 24 Pipe group 25 Closure

Claims (12)

[Claims] In a method of drilling a hard ground by a down-the-hole drill and injecting and filling a grout material, after reaching a target depth of a drilling step, a compressed air supply path to a bit of the down-the-hole drill is passed. And filling the grout material into the drilled hole through the down-the-hole drill through the air ejection port of the down-the-hole drill via pressure feeding. 2. A grout through a down-the-hole drill according to claim 1, wherein in the injection, compressed air is supplied simultaneously with the pressurization of the grout material so as to facilitate the injection and filling of the grout material. Filling method in the hole by material injection. 3. The grouting material filling and filling method, wherein a pipe group is attached to an outer periphery of the down-the-hole drill, and drilling is performed while protecting a hole wall. 3. A method for filling a drilled hole by injecting a grout material through a down-the-hole drill according to any one of claims 1 and 2, characterized in that: 4. The down-the-hole according to claim 3, wherein the grout material is injected and filled while the tip of the down-the-hole drill is rotated so that the tip of the down-hole drill can freely project beyond the inside of the pipe group. A method of filling grind holes by grout injection through a drill. 5. The down-the-hole drill according to claim 4, wherein, when the grout material is injected and filled, an end of the down-the-hole drill projects forward from an end of the pipe group and is enlarged. Filling method into the hole by grouting material injection through 6. The method for injecting and filling a grout material according to claim 1,
By attaching a group of pipes to the outer periphery of the down-the-hole drill where the tip bit can be freely expanded and reduced, drilling of the drill hole and embedding of the pipe group proceed simultaneously and simultaneously, grouting and filling into the drill hole. When injecting and filling the grout material into the gap between the pipe group and the drilling wall, closing any position of the ring-shaped gap formed by the inner circumference of the pipe group and the outer circumference of the drill rod, or The gap between the inner periphery of the pipe group and the down-the-hole drill by injecting and filling the grout material into the pipe is sealed, thereby suppressing the injection of the grout material into the gap between the down-the-hole drill and the pipe group in the pipe group. The grout material can be injected and filled into the gap between the outer peripheral surface of the hole and the drilling wall freely through the down-the-hole drill according to any one of claims 2 and 3. Filling method into drilled by Raut material injection. 7. The method for injecting and filling a grout material according to the present invention,
3. The grout material is injected and filled from an air ejection port of the down-the-hole drill via a compressed air supply path of the down-the-hole drill when the group of pipes is left in the hole. 7. A method for filling holes into a hole by grout material injection through a down-the-hole drill according to any one of Items 7 to 7. 8. A grout material through a down-the-hole drill according to claim 8, wherein, when the grout material is injected and filled, different grout materials are injected and filled inside and outside as a partition of the pipe group. A method of filling holes into holes. 9. The method according to claim 8, wherein the grout material is injected and filled in such a manner that different grout materials are injected and filled in a plurality of upper and lower layers outside the partition wall of the pipe group. A method of filling grind holes by grout material injection through the down-the-hole drill as described. 10. A down-the-hole drill, wherein different grout materials are injected and filled into the inside of the pipe group and the upper and lower layers of the pipe group when the grout material is injected and filled. A method of filling grind material into a drilled hole. 11. A grout material injection through a down-the-hole drill according to any one of claims 2 to 11, wherein said pipe group is left and fixed as an underground structure. Method for filling into the drilled hole. 12. The grout injection and filling method according to claim 12, wherein a sealing device is disposed at any position of the pipe group after reaching a target drilling depth, wherein the grout is injected through a down-the-hole drill. A device for filling holes.