KR20100003980A - Method of improving soft ground with expansion tube - Google Patents

Abstract

PURPOSE: A soft ground improvement method using an expansion tube is provided to maximize improvement effect compared with an existing soft ground improvement method and to use the expansion tube as a pile by filling the expansion tube with sand or gravel. CONSTITUTION: A soft ground improvement method using an expansion tube comprises the following steps. An expansion tube(10) is inserted into each perforated hole(1) after perforating a soft ground. A drain material(30) is formed in the gaps among the expansion tubes. Water is injected inside the expansion tube.

Description

Method for improving soft ground with expansion tube

The present invention is to install an expandable tube (hereinafter referred to as 'expansion tube') in the drilling hole after drilling at regular intervals to the depth of the object of improvement, and used for improving the existing soft ground between the installed expansion tube and the expansion tube It is a method to improve the soft ground to be improved by using the principle of forced horizontal consolidation by pouring water inside the expansion tube and expanding it from the bottom after completing the installation in the same way as the drain material construction method. In addition to maximizing the improvement effect (simplification of construction, convenient on-site management, drastic reduction of consolidation time, etc.), after filling the soil, the expansion tube is filled with sand or gravel (including crushed stone), grouted, or poured concrete. It relates to a soft ground improvement method using an expansion tube that can also be used as.

Soft ground generally contains a lot of fine particles such as clay and silt, and the groundwater level is high in most rivers and beaches. These grounds must be improved in order to build structures (buildings, roads, etc.) because the ground loads are not only largely settled by weight, but also have low bearing capacity.

The characteristics of the existing soft ground improvement methods are described in detail in the table below. Among them, Sand Drain, Paper Drain, and Pack Drain methods do not cause shear failure of soft ground for the purpose of installing drain material in the ground and promoting consolidation using equipment inside the ground to improve drain material. It is a construction method that promotes improvement by filling the surface with a certain height within the range.

  Type of construction      summary      Advantages     Disadvantages PRE-LOADING METHOD Method to promote consolidation settlement by load 1. Reduced construction time 2. Low construction cost 3. Easy quality control during construction 1. Long consolidation period 2. The deeper the depth of the improved ground, the lower the improvement effect compared to other methods. SAND DRAIN method Horizontal drainage by installing sand pillars vertically 1. Increasing ground strength by sand 2. Shortening settlement time 3. Good ground improvement effect 1. Nonuniformity and discontinuity of sand column section in the ground with large water ratio 2. Possible to cut the column during stress concentration 3. Decreasing reliability of column continuity by arching    PAPER DRAIN Method Horizontal drainage by installing the drain board in the ground 1. Drainage effect schedule 2. Easy to handle drainage. 3. Good construction speed 4. Low construction cost 1. Poor drainage function due to side pressure and consolidation 2. Possible to rupture coating material 3. No increase in ground strength due to material strength 4. Difficult to construct in ground having N value of more than 10     PACK DRAIN method Horizontal drainage with sand pillars protected by a permeable bag 1. No imbalance and discontinuity of DRAIN 2. Maintain size of cross section during consolidation 3. Easy to manage construction. 4. Adjustable sand amount according to diameter size of protective material 1.Residual settlement increase in uneven ground 2.Possibility of ground disturbance during construction 3.Package assembly assembly increase 4.Pack permeability decreases

Common features of the existing methods described above are various disadvantages (longer consolidation time, site of large equipment) due to the improvement of the soft ground by horizontal consolidation in the natural state after the drain material is installed in the ground and the load is loaded. Difficulty in entry, loading of embankment to promote consolidation, and the strength of the improved ground hardly improved from the bottom to the top).

In addition, shearing may occur in the soft ground when a large amount of fill is carried out to promote consolidation.

In addition, the existing soft ground method has a drawback that if the depth of improvement is deep, the improvement effect is not only degraded, but if the shear occurs in the ground, the drain material is cut, the residual settlement may occur a lot after the soft ground improvement.

In order to solve such a problem, it is proposed as a conventional soft ground improvement method disclosed in, for example, the publication of Korea Patent No. 10-0398721.

In the soft ground improvement method according to this publication, an inflated drain having a structure in which a vinyl tube is installed inside a corrugated nonwoven fabric covered with a nonwoven fabric is installed into the ground of the soft ground, and then installed inside the inflated drain. By injecting air using a separate air inlet through the check valve of the structure attached to the upper end of the vinyl tube, a small amount of drainage layer and fill layer are contained in the soft ground by using the expansion pressure that the vinyl tube expands. It is proposed to dehydrate the water quickly and reliably, and it is possible to shorten the construction period and reduce the construction cost by simplifying the installation and installation work in the soft ground mainly for the construction of roads.

However, due to the expansion of the vinyl tube, the corrugated nonwoven fabric drain also expands and horizontally consolidates to the surrounding nonwoven corrugated nonwoven drainage structure, so the horizontal consolidation transfer rate is slow and takes a long time to consolidate.

In addition, if the horizontal consolidation is similar between the infused drain and another infused drain, there is a concern that the groundwater may stagnate between the infused drain and the other infill drain.

In addition, when there is a large difference in horizontal consolidation between the inflated drain and the other infused drain, there is a high possibility that the groundwater is pushed toward the weak horizontal consolidation, so that uniform drainage is difficult.

In addition, because of the expansion by light air, when the depth of improvement is deep, not only the improvement effect is reduced, but also the amount of residual sedimentation in uneven ground becomes a problem.

In addition, there is a need for bonding the corrugated nonwoven fabric drain and the vinyl tube.

In addition, there is a hassle to remove the inflated drain when the hole is to be filled up to the ground depth after completion of the drain operation.

In addition, when the inflated drain is not removed, the non-woven fabric and the vinyl may not serve as a support pile.

The present invention has been made in order to achieve the above object, it is possible to improve uniformly throughout the range of the soft ground through the appropriate arrangement of the expansion tube and drain material and to improve the horizontal horizontal step by step from bottom to top The purpose is to provide a soft ground improvement method using an expansion tube that can be less affected by depth.

In order to achieve the above object, the soft ground improvement method using the expansion tube according to claim 1 of the present invention,

Inserting expansion tubes into each of the perforation holes after drilling in the soft ground at predetermined intervals; installing drain material between the installed expansion tube and the expansion tube; and when injecting water into the expansion tube. And a step of forcibly horizontal consolidation by the pressure expanded from the lower part, and the step of draining the groundwater through the drain material to the surface by the forced horizontal consolidation.

According to this process, since the drain material is provided in the soft ground between the expansion tube and the expansion tube, even if the expansion force between the expansion tube is different, it can penetrate into the drain material and drain almost uniformly over the entire improvement range of the soft ground. Forced horizontal consolidation from the lower part to the upper part makes the influence of the depth of improvement small and the ground after the improvement can have almost insignificant strength even if the strength of the ground is partially different before the soft ground is improved. The calculation of can be more accurate than conventional methods.

Soft ground improvement method using the expansion tube according to claim 2 of the present invention,

After completing the drainage of the ground water, it is preferable to include a step of constructing the pile by filling the inside of the expansion tube.

According to this process, it is possible to use sand or gravel (including crushed stone), grout, or cast concrete in the expanded tube after completion of the ground improvement, and use it as a site casting pile. Especially for the purpose of constructing roads, sports grounds, and structures (structures with low self-weight, etc.), it is possible to minimize settlement due to the arching effect generated in pile heads by depositing high-quality soil of a certain thickness on the upper surface of the surface.

As apparent from the above description, the soft ground improvement method using the expansion tube according to the embodiment of the present invention has the following effects.

Since the ground load is not loaded on the surface after the expansion tube and the drain material are installed in the soft ground for the purpose of improvement, the construction period and the construction cost for the ground can be reduced, and the shear failure of the soft ground due to the ground load can be prevented. .

In addition, it is a method of promoting horizontal drainage by forcibly horizontal consolidation by increasing the volume while expanding water from the bottom by expanding water from the lower part, so that the ground improvement time is much shorter than the existing method without embankment load, and the strength of the improved ground is lower to upper part. It is the greatest advantage of the present invention to be improved almost constantly.

In addition, the existing soft ground method is not only the improvement effect is reduced when the depth of improvement is deep, but the residual settlement that is generated after the cutting or improvement of the drainage is a problem, but the method of the present invention has a small effect by the depth of improvement and the soft ground Regardless of the partially different strength, it can be improved in any soil, and the strength of residual sediment can be calculated more accurately than the existing method since it can have the same strength of soil after the improvement.

In addition, after the completion of the improvement, filling or grouting the sand or gravel inside the expansion tube can be cast as concrete to be used as a site-placement pile, especially for the purpose of building roads, playgrounds, structures (structures with low weight), etc. The sedimentation can be minimized by the arching effect on the pile head by depositing high quality soil on the upper surface of the surface.

In addition, after completion of the expansion tube and drain material construction, the upper part of the expansion tube is exposed to the surface, and when the horizontally drained groundwater is discharged to the surface through the drain material, it is easy to manage construction because it makes a trench in the surface.

In addition, the design can be easily proved by existing theoretical formulas, and the construction method does not require special know-how.

In addition, in terms of material cost, the expansion tube is additionally manufactured and constructed, but the cost of construction is increased.

In addition, in consideration of the advantages and disadvantages of the existing soft ground improvement method can be expected to achieve even greater improvement effect when mixed expansion tube method.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings, wherein the term filling is intended to include grouting or concrete pouring.

1 is a cross-sectional view illustrating a state in which an expansion tube and a drain material are installed in an improved method according to a preferred embodiment of the present invention, and FIG. 2 illustrates that the ground water is drained through the drain material by injecting water into the expansion tube in FIG. It is sectional drawing which shows the state to make, and FIG. 3 is the top view of FIG.

As shown in Figures 1 to 3, the soft ground improvement method according to this embodiment first prepares the expansion tube 10 and the drain material (30).

The expansion tube 10 is excellent in expandability, it is preferable to use a material (for example, rubber or vinyl) that is not easily damaged by defects when the ground is poured during the installation or in the ground to improve the ground by pouring water.

The drain material 30 is a drain material installed vertically on the ground in order to apply the expansion tube method, it can be used as all existing drainage material (for example, a drain board or non-woven cardboard, such as synthetic resin).

Next, as shown in Fig. 3, the soft ground for improvement is drilled at a predetermined (constant) interval (lattice arrangement) to the improved target depth by using the equipment, and then the expansion tube 10 is formed inside the drilling hole 1. Insert).

Insertion of the expansion tube 10 may be by the injection of water (W) described below, in the case of a rubber tube may be pre-push to the depth of the drilling hole (1) and then water (W).

For this reason, the expansion tube 10 may vary depending on the material, but may be used in the form of a sheet (when the sheet is formed into a tube while injecting water), or the sheet is formed in the same shape as the depth of drilling (ie, in the form of a tube). It can be used (if it has been pushed in before water injection).

Therefore, in any case, making the tube form is very simple.

Next, the drain material 30 is inserted and installed to an improved depth between the expansion tube 10 and the expansion tube 10 inserted into the drilling hole 1. No fill load is necessary at this time.

Due to this arrangement, since the expansion tube 10 and the drain material 30 are spaced apart from each other by a constant horizontal consolidation according to the expansion force of the expansion tube 10, the groundwater is quickly drained through the drain material 30. Can be. Therefore, the construction time can be greatly improved, thereby reducing the construction period and construction cost.

The drain material 30 is inserted and installed in the same manner as the existing construction method on the soft ground for the purpose of improvement.

After the expansion tube 10 and the drain material 30 are all installed, water (W) is injected into the expansion tube 10 as shown in FIG. 2.

The injection of water W is filled from the bottom and expands stepwise upwards. In other words, as shown in Fig. 2, they are filled up in the order of ①-> ②-> ③-> ④-> ⑤.

Since the horizontal consolidation step by step is forcibly horizontal consolidation from the bottom of the expansion tube in turn even if the depth of improvement is deep, there may be a difference in time consolidation according to the depth.

Therefore, since the constant improvement from the bottom to the top is not only less influenced by the depth of improvement, the calculation of the residual sedimentation can also increase the accuracy compared to the existing method.

In addition, when the improvement range is limited to one zone, the order of injecting water (W) into the expansion tube 10 is generally preferred to start from the outside of the improvement range and end at the center in order to maximize the improvement effect.

That is, when water (W) is sequentially injected from the outer expansion tube (10) toward the center expansion tube (10), the groundwater is confined, so that the improvement effect of the soft ground can be more surely performed. The order may be changed according to site conditions.

By using the expansion pressure of the expansion tube 10 such as to force the horizontal consolidation drain through the drain material (30).

When the drained water is discharged to the surface through the drain material 30, a trench is formed in the surface to guide the waterway, so construction management is easy.

After the improvement of the soft ground is completed, filling the filling (sand, gravel, concrete, cement milk, etc.) in the expansion tube 10 can be used as a cast site pile. That is, the filling material may be implemented in the form of filling gravel or sand, grouting or placing concrete.

Especially for the purpose of constructing roads, sports grounds, and structures (structures with small weights), it is possible to deposit high-quality soil of a certain thickness on the upper surface of the ground so that residual settlement does not occur by the arching effect generated in the pile head. have.

As such, when the filling is filled in the expansion tube 10, the water (W) is naturally discharged to the surface. Sand or gravel is sinking down by weight, and water is discharged by buoyancy, and concrete or cement milk is discharged when it is pushed up when it is poured under the drilling hole (1).

As described above, although described with reference to a preferred embodiment of the present invention, the present invention can be variously modified or modified without departing from the spirit and scope of the present invention described in the claims Those skilled in the art will appreciate.

The construction method of the present invention has the advantage that it can be used as a site-placement pile by shortening the construction period by separately installing the expansion tube and the drain material and filling or grouting or grouting the gravel or sand in the expansion tube after completion of the construction, You can mix and use the advantages of the existing method.

1 is a cross-sectional view showing a state in which the expansion tube and the drain material installed in the improved method according to a preferred embodiment of the present invention.

Figure 2 is a cross-sectional view showing a state in which the ground water is drained through the drain material by injecting water into the expansion tube in FIG.

3 is a plan view of FIG.

<Explanation of symbols for the main parts of the drawings>

10: expansion tube 30: drain material

Claims (2)

Inserting expansion tubes into each of the perforation holes after perforating the soft ground at predetermined intervals; Installing a drain material between the installed expansion tube and the expansion tube; Forcibly horizontal consolidation by the pressure that is expanded from the bottom when the water is injected into the expansion tube, Soft ground improvement method using an expansion tube comprising the step of draining the groundwater through the drain material to the surface by the forced horizontal consolidation. The method of claim 1, After completing the drainage of the ground water, the method for improving the soft ground using expansion tube comprising the step of constructing the pile by filling the inside of the expansion tube.

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