JP7413168B2 - Compaction method - Google Patents

Description

The present invention relates to a compaction method (static press-in compaction method) in which surrounding ground is compressed and compacted by creating an improved body by injecting improving material into a plurality of holes formed in the ground.

The static press-in compaction method used for ground improvement is generally referred to as the CPG method (compaction grouting method) or the SAVE method, and compared to the SCP method (sand compaction pile method), vibration and noise are extremely high. It is said to be a ground compaction method that is environmentally friendly. In the static press-in compaction method, improved material is injected (press-fitted) into the ground to create an improved body, and the compaction effect of this improved body compresses and strengthens the surrounding ground. Patent Document 1 discloses an example of a static press-in compaction method.

Patent No. 5598999

However, in construction using the static press-in compaction method, managing the amount of ground upheaval is extremely complicated.
In view of the above-mentioned circumstances, the present invention aims to propose a rational method for managing the amount of upheaval in the static press-in compaction method.

Therefore, the compaction method according to the present invention compresses and compacts the surrounding ground by creating an improved body by injecting an improving material into a plurality of holes formed in the ground. The compaction method according to the present invention includes a first step of obtaining the planar distribution of the amount of ground upheaval caused by injecting the improving material into one drilled hole, and a step of obtaining the planar distribution of the amount of ground upheaval caused by injecting the improving material into one drilled hole. , a second step of calculating the total amount of uplift in the ground assuming that the planar distribution of the amount of uplift of the ground obtained in the first step occurs; and a second step of calculating the total amount of uplift in the ground calculated in the second step. and a third step of comparing the predetermined value and the predetermined value. If the total amount of upheaval exceeds a predetermined value in the third step, the construction control value when injecting the improvement material into one drilling hole and/or the injection method of the improvement material so as to reduce the total amount of upheaval. change.

According to the present invention, it is possible to predict the overall amount of upheaval in the ground and proceed with construction in a manner that deals with this, so it is possible to manage the amount of uplift in the ground more easily than in the past.

A diagram showing a schematic configuration of a construction system in an embodiment of the present invention Diagram showing an image of the uplift of the ground when injecting improvement material into a single borehole Flowchart showing the first example of the work flow of the compaction method Flowchart showing the second example of the work flow of the compaction method Flowchart showing the third example of the work flow of the compaction method A plan view showing the arrangement of holes in a specific example of the compaction method Diagram showing the calculation results of the total uplift amount in a specific example of the compaction method Overall uplift amount control chart for a specific example of compaction method Individual uplift amount control chart for a specific example of compaction method Diagram for explaining the uplift amount management method using an individual uplift amount control chart in a specific example of the compaction method Diagram for explaining the uplift amount management method using the overall uplift amount control chart in a specific example of the compaction method Diagram showing the schematic configuration of a screen device that can be incorporated into the construction system Diagrams showing a first modification and a second modification of the screen device A diagram showing a third modification of the screen device

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a schematic configuration of a construction system according to an embodiment of the present invention.

In this embodiment, an example of a compaction method (static press-in compaction method) in which the surrounding ground is compressed and compacted by creating an improved body by injecting improving material into a plurality of holes formed in the ground. The CPG construction method using the construction system shown in FIG. 1 will be explained below. However, it goes without saying that the above-mentioned SAVE construction method is also applicable.

The construction system 100 includes an injection pipe 101, a flow rate pressure monitoring device 103, an improved material pressure feeding pump 104, an improved material production plant 105, an auger mixer 106, and pressure feeding hoses 107 and 108.

The injection pipe 101 is a renamed borehole pipe built into the ground using a boring machine (not shown). The improvement material generation plant 105 generates improvement material (ground improvement material). This improved material is a hardened mortar with extremely low fluidity, for example, a slump value of 5 cm or less, and contains cement as a hardening agent, water, and sand (for example, what is called CPG aggregate). include. The auger mixer 106 conveys the improved material produced in the improved material production plant 105 to the hopper 104a of the improved material pressure pump 104 (see FIG. 12 described later). The improvement material pressure pump 104 has a structure similar to, for example, a piston-type concrete pump. The improvement material pressure feeding pump 104 corresponds to the "improvement material injection pump" of the present invention. The discharge side of the improvement material pressure pump 104 is connected to the inlet of the flow rate pressure monitoring device 103 via a pressure hose 107 . The flow rate pressure monitoring device 103 is provided with display means or output means for monitoring the flow rate (injection amount) and pressure (injection pressure) of the improvement material. The outlet of the flow rate pressure monitoring device 103 is connected to the upper end of the injection pipe 101 via a pressure hose 108.

In the static press-in compaction method using the construction system 100, first, a hole is drilled to a predetermined depth while erecting the injection pipe 101 (boring pipe) into the ground. When the lower end of the injection pipe 101 reaches the target depth, the injection pipe 101 in the penetrating state is connected to the improvement material pressure pump 104 via the pressure feed hose 108, the flow rate pressure monitoring device 103, and the pressure feed hose 107. The improved material produced in the improved material production plant 105 is sent to the improved material pressure feeding pump 104 via the auger mixer 106, and is further pressure fed from the improved material pressure feeding pump 104 to the pressure feeding hose 107, the flow rate pressure monitoring device 103, and the pressure feeding pump 104. It is press-fitted into the ground via a hose 108 and an injection pipe 101. In the step of press-fitting the improved material, for example, pressure feeding of the improved material and step-up of the injection pipe 101 at fixed depth intervals (pulling up the injection pipe 101) are repeated.

The improvement material press-fitted into the ground forms an improvement body (lump of improvement material) 150 at a predetermined position without straying or penetrating in the soil. Therefore, by repeating the pumping of the improvement material by the improvement material pressure pump 104 and the step-up of the injection pipe 101, a plurality of bulb-shaped improvement bodies 150 as shown in FIG. 1 are continuously created. Then, by compressing the surrounding ground by increasing the volume of each improvement body 150 and increasing the density (that is, by compacting it), the ground can be improved.

In this embodiment, a hole (injection hole) 110 (see FIG. 2) is formed in the ground by erecting the injection pipe 101 into the ground. Furthermore, in this embodiment, the improvement material 150 is created in the ground by injecting (pressing) the improvement material pumped from the improvement material pressure pump 104 into the borehole 110 via the injection pipe 101. Note that the drilled holes 110 are often arranged in a triangular arrangement (see FIG. 6, which will be described later) or in a rectangular arrangement at intervals of 1.6 to 2.0 m in plan view.

FIG. 2 is a diagram showing an image of the upheaval of the ground when the improvement material is injected into one drilled hole 110. Here, FIG. 2 shows an example of soil improvement using the static press-in compaction method for soft ground at a depth of GL-3m to -15m. Further, in FIG. 2, illustration of a portion of the hole 110 corresponding to depths GL-0m to -3m is omitted.

In this example, from the state where the lower end of the injection pipe 101 has reached the depth GL-15m (target depth), the injection pipe 101 is intermittently raised in steps (one step thickness 0.33m) and the improved material is injected. do. Based on past construction results and test construction, it has been found that the amount of ground upheaval is large at depths between GL-5m and -3m, and almost never occurs at depths below GL-5m. In this regard, the uplift shape P1 in FIG. 2 shows an image of the planar distribution of the amount of uplift of the ground for each step at depths GL-5m to -3m. In addition, the protrusion shape P2 in FIG. 2 represents the planar distribution of the amount of elevation of the ground when the improvement material is injected into the portion of the drilled hole 110 corresponding to the depth GL -3m to -15m (in other words, the above-mentioned An image of the integrated value (total value) of the planar distribution of the amount of ground uplift for each step is shown.

FIG. 3 is a flowchart showing a first example of the work flow of the static press-in compaction method in this embodiment.

In this example, first, prior to step S1, the following methods [1] to [5] are set as the improving material injection method.

[1] Number, depth, planar arrangement, and spacing of the drilled holes 110 formed in the construction target area of the ground [2] Construction order (improvement) of the plurality of drilled holes 110 in the ground construction target area material injection order)
[3] Sequence of creating a plurality of improved bodies 150 in the vertical direction by injecting improved material into one drilled hole 110 [4] Operation mode (operation mode) of improved material pressure pump 104
[5] Time interval of improvement material injection timing between adjacent drilling holes 110

Further, prior to step S1, the following [6] to [10], for example, are set as construction management values.

[6] Upper limit PM of injection pressure of improved material
[7] Target value GT of the injection rate, which is the ratio (area ratio or volume ratio) of the improvement material in the ground
[8] Upper limit value of the total uplift amount of the ground, which is the total uplift amount of the construction target area of the ground LT0
[9] Upper limit value SM of the amount of ground uplift for each step when injecting improvement material into one drill hole 110
[10] Upper limit TM of the total amount of elevation of the ground when injecting improvement material into one drilling hole 110

Here, [8] the upper limit value LT0 of the total uplift amount of the ground corresponds to the "predetermined value" of the present invention. [9] Upper limit value SM of the amount of ground uplift for each step when injecting improvement material into one drilling hole, [10] Upper limit value of the total uplift amount of the ground when injecting improvement material into one drilling hole. TM, [6] Upper limit value PM of the injection pressure of the improved material, and [7] Target value GT of the injection rate correspond to the "construction control value when injecting the improved material into one drilling hole" of the present invention. It is something.

Next, in step S1, the planar distribution of the amount of upheaval when the improvement material is injected into one drilled hole 110 is obtained (step of obtaining planar amount distribution of upheaval). This step corresponds to the "first step" of the present invention. In this process, the above-mentioned planar distribution is obtained by test injecting the improvement material into one borehole 110, or the finite element method (FEM) is used to obtain the above-mentioned planar distribution without actually injecting the improvement material into the ground. The above-mentioned planar distribution is obtained through numerical analysis such as The test injection here means performing a test injection work of improving material in one drilled hole 110 in the construction target area of the ground.

In this process, when obtaining the planar distribution of the amount of upheaval when injecting the improving material into one drilled hole 110, the above-mentioned [6], [7], and [9] are performed regarding the injection of the improving material in each step. When one of these steps is reached, the injection of the improvement material in that step is completed and the step moves to the step above it. Then, repeat the injection of the improvement material for each step, and if the above-mentioned [10] is reached before the injection of the improvement material in the final step (the top step), the setting value is set prior to step S1. The method of injection of improving materials and/or construction control values may be reviewed. That is, depending on the results of the above-mentioned test injection or numerical analysis, the method of injection of the improvement material and/or the construction control value may be reviewed.

Next, in step S2, it is assumed that the planar distribution of the amount of ground uplift obtained in step S1 described above will occur due to the injection of the improvement material for each of all the drilled holes 110 in the area to be constructed in the ground. Then, the total uplift amount LT1 in the ground is calculated (total uplift amount calculation step). This step corresponds to the "second step" of the present invention.

The total uplift amount LT1 in the ground is a predicted value of the entire uplift amount in the construction target area of the ground, and is calculated based on the planar distribution of the uplift amount of the ground acquired in step S1 above and all of the ground in the construction target area. can be calculated based on the position (coordinates) of the drilled hole 110.

Next, in step S3, the total uplift amount LT1 of the ground calculated in step S2 is compared with the upper limit value LT0 of the total uplift amount of the ground that was set prior to step S1 (total uplift amount confirmation step). This step corresponds to the "third step" of the present invention.

In step S3, if the total upheaval amount LT1 is less than the upper limit value LT0 of the total upheaval amount (LT1≦LT0), the process proceeds to step S5, and the individual Create an uplift amount control chart and an overall uplift amount control chart (construction control chart creation process).

On the other hand, in step S3, if the total upheaval amount LT1 exceeds the upper limit value LT0 of the total upheaval amount (LT1>LT0), the process proceeds to step S4, and the total upheaval amount LT1 is decreased (for example, Change at least one of the above [1] to [7], [9], and [10] so that the total uplift amount LT1 is equal to or less than the upper limit value LT0 of the total uplift amount (construction control value/injection method). change process). After that, the process proceeds to step S5, and an individual uplift amount control chart and an overall uplift amount control chart are created in which the changes made in step S4 are taken into account (construction control chart creation step).

In step S4, when the above-mentioned [3] is changed, the order in which a plurality of improved bodies 150 are created in the vertical direction can be changed by injecting the improving material into one drilled hole 110. This may include changing the injection method of the improving material from the bottom-up method described in Patent Document 1 to the top-down method. Here, the bottom-up method is a method in which a plurality of improved bodies 150 are created in order from the lower end of the improved depth upwards. Furthermore, the top-down method is a method in which a plurality of improved bodies 150 are created in order from the top of the improvement depth to the bottom. Note that the method of injecting the improving material may be changed so as to combine the top-down method and the bottom-up method.

In step S4, when changing [4] above, the operation mode of the improved material pressure pump 104 is such that the improved material is injected while repeating loading and unloading on the improved material using the improved material pressure pump 104. may be changed. The mode of operation of this improvement material pressure pump 104 is an improvement material injection method generally referred to as a "reverse method", and one example thereof is disclosed in Japanese Patent No. 5119381.

In step S4, when the above-mentioned [5] is changed, the time interval between the improvement material injection timings is widened with respect to the adjacent drilled holes 110, and the amount of upheaval is waited for to return.

The individual uplift amount control chart created in step S5 is used for each drilled hole 110 when injecting improvement material into each of all the drilled holes 110 in the construction target area of the ground. This individual uplift amount control chart is, for example, a relationship diagram between the uplift amount of the ground when the improvement material is injected into one drilling hole 110 and the injection depth of the improvement material (see FIG. 9, which will be described later).

The overall uplift amount control chart created in step S5 is used to manage the construction status of the entire construction target area of the ground. This overall uplift amount control chart shows, for example, the uplift amount of the ground at the formation location of each drilled hole 110 and the amount of uplift within the ground construction target area for some of the drilled holes 110 arbitrarily selected within the ground construction target area. 8 is a diagram showing the relationship between the number of drilled holes 110 in which the improvement material has been injected (see FIG. 8, which will be described later). By using this overall uplift amount control chart, the above injection amount of uplift of any drill hole 110 when the improvement material injection work is performed in the arbitrary drill hole 110 and the drill holes 110 in its influence range according to the planned order. It is possible to grasp the transition according to the progress of the work.

Next, in step S6, the above-mentioned individual uplift amount control chart and overall uplift amount control chart are used to manage the construction within the construction target area of the ground and proceed with the construction. Needless to say, in this construction, the construction control values and the method of injecting the improvement material, which were the basis for creating the individual uplift amount control chart and the overall uplift amount control chart, are used.
In this example, the construction progresses while the construction management of the ground improvement is performed as described above.

FIG. 4 is a flowchart showing a second example of the work flow of the static press-in compaction method in this embodiment.
The differences from the first example of the work flow of the static press-in compaction method shown in FIG. 3 will be explained.

In this example, in step S3, if the total upheaval amount LT1 exceeds the upper limit value LT0 of the total upheaval amount (LT1>LT0), the process proceeds to step S4, and the total upheaval amount LT1 is decreased ( For example, at least one of the above [1] to [7], [9], and [10] is changed so that the total uplift amount LT1 is equal to or less than the upper limit value LT0 of the total upheaval amount. After that, the process returns to step S2, and the total upheaval amount LT1 in the ground is recalculated (that is, recalculated). Then, in step S3, the total uplift amount LT1 is compared with the upper limit value LT0 of the total uplift amount. By doing so, the validity of the change made in step S4 can be confirmed, and if the change is insufficient, the change can be reviewed.

FIG. 5 is a flowchart showing a third example of the work flow of the static press-in compaction method in this embodiment.
The differences from the first example of the work flow of the static press-in compaction method shown in FIG. 3 will be explained.

In this example, in step S3, if the total upheaval amount LT1 exceeds the upper limit value LT0 of the total upheaval amount (LT1>LT0), the process proceeds to step S4, and the total upheaval amount LT1 is decreased ( For example, at least one of the above [1] to [7], [9], and [10] is changed so that the total uplift amount LT1 is equal to or less than the upper limit value LT0 of the total upheaval amount. Thereafter, the process returns to step S1, and the planar distribution of the amount of upheaval when the improvement material is injected into one drilled hole 110 is acquired again. Then, using this re-acquired planar distribution of the uplift amount, the total uplift amount LT1 in the ground is calculated in step S2, and the total uplift amount LT1 is compared with the upper limit value LT0 of the total uplift amount in step S3. . By doing so, the validity of the change made in step S4 can be confirmed, and if the change is insufficient, the change can be reviewed.

Next, a specific example of the static press-in compaction method in this embodiment will be explained using FIGS. 6 to 11. FIG. 6 is a plan view showing the arrangement of the drilled holes 110 in this specific example. FIG. 7 is a diagram showing the calculation result of the total protrusion amount LT1 in this specific example. FIG. 8 is a total upheaval amount management chart in this specific example. FIG. 9 is an individual uplift amount control chart in this reference example. FIG. 10 is a diagram for explaining an uplift amount management method using an individual uplift amount management chart in this specific example. FIG. 11 is a diagram for explaining the uplift amount management method using the overall uplift amount management chart in this specific example.

Here, hole numbers 1 to 37 shown in FIG. 6 and hole numbers 1 to 50 shown in FIGS. 7 and 8 each correspond to the hole 110 described above. The drill hole number here indicates the order in which the improvement material is injected into the plurality of drill holes 110 formed within the construction target area of the ground. That is, for the plurality of holes 110, the improvement material is injected in the order of the hole numbers.

FIG. 6 shows hole numbers 1 to 3 and 5 to 37 that affect the prominence of hole number 4. In this specific example, the affected range of drill hole number 4 is within a circle Q with a radius of 6 m centered on drill hole number 4 in plan view.

This specific example will be described below as being in line with the first example of the work flow of the static press-in compaction method shown in FIG. 3 above. Furthermore, this specific example shows an example in which hole number 4 among the plurality of drill holes 110 in the construction target area of the ground is selected in order to grasp the total uplift amount.

In this specific example, prior to step S1, the above-mentioned [6] to [10] are set as follows.

[6] Upper limit of injection pressure of improved material PM = 6MPa
[7] Injection rate target value GT = 8%
[8] Upper limit of total elevation of the ground LT0 = 150mm
[9] Upper limit of the amount of ground upheaval for each step when injecting improvement material into one drill hole 110 SM = 2 mm
[10] Upper limit of the total amount of elevation of the ground when injecting improvement material into one drill hole 110 TM = 14 mm

In this specific example, in step S1, the planar distribution of the amount of upheaval when the improving material is injected into one drilled hole 110 is a conical upheaval amount distribution with a radius of 6 m on the circular bottom and a height (upage amount) of 14 mm. shall be assumed to have been obtained.

In this specific example, in step S2, the relationship diagram shown in FIG. 7 can be obtained regarding drilling hole number 4. By using this relationship diagram, it is possible to calculate the amount of upheaval of hole number 4 when the improvement material injection work is performed in hole number 4 and hole numbers 1 to 3 and 5 to 37 in its affected range according to the planned order. It is possible to grasp the transition α1 according to the progress of the injection work. In this relationship diagram, the total protrusion amount LT1=152.52 mm.

In this specific example, in step S3, the total upheaval amount LT1 exceeds the upper limit value LT0 of the total upheaval amount (LT1>LT0) with respect to drilling number 4, so the process proceeds to step S4 and the total upheaval amount LT1 is reduced. (For example, so that the total uplift amount LT1 is equal to or less than the upper limit value LT0 of the total upheaval amount.) [10] and [9] above are changed.

In this specific example, [10] the upper limit TM of the total amount of elevation of the ground when injecting improvement material into one drilled hole 110 is changed using the following formula.
14 x (150/152.52) = 13.76mm

In accordance with this change in the upper limit value TM of the total amount of uplift, in this specific example, [9] the upper limit value SM of the amount of uplift of the ground for each step when injecting improvement material into one drilled hole 110 is determined by the following formula. change.
2 x (13.76/14) = 1.97mm

After that, in step S5, the overall uplift amount control chart shown in FIG. 8 and the individual uplift amount control chart shown in FIG. 9 are created, and in step S6, the construction target area of the ground is created using these control charts. The construction will proceed while managing the construction within the company.

The individual uplift amount control chart shown in Figure 9 manages the upper limit SM of the amount of ground uplift for each step between GL-5m and -3m as 1.97mm, and below GL-5m, the total amount of uplift is controlled. The management boundary line α3 is set so that the upper limit value of is managed as 1.97 mm. In this individual uplift amount control chart, the control boundary line α3 is set so that the total uplift amount of the ground when the improvement material is injected into one drilling hole 110 is suppressed to the upper limit value TM = 13.76 mm or less. There is. By setting this control boundary line α3 as a control value and controlling the construction so that the actual measured value is located above it, all steps when injecting improvement material into one drilled hole 110 can be performed without exception, and , [10] The upper limit of the total amount of elevation of the ground when injecting improvement material into one drilled hole 110 can be maintained at 13.76 mm. This situation is shown in FIG.

By using the overall upheaval amount control chart shown in Figure 8, it is possible to calculate the results for drilling hole number 4 and hole numbers 1 to 3 and 5 to 37 in its affected area when the improvement material injection work is performed in accordance with the planned order. It is possible to set a management value (reference value) α2 of the transition of the amount of protrusion No. 4 according to the progress of the injection work. In this overall upheaval amount control chart, the management value α2 of the above transition is set so that the overall upheaval amount is suppressed to the upper limit value LT0=150 mm or less. If the construction is managed so that the actual measured value is less than the control value α2 of this transition, [8] all the drilling holes 110 in the construction target area of the ground will be The desired improvement material injection work can be carried out without fail. This situation is shown in FIG.

The overall uplift amount control chart shown in FIG. 8 was created for the drill hole 110 corresponding to hole number 4, but it may be created for any drill hole 110 within the construction target area of the ground. Needless to say.

By the way, in the conventional static press-in compaction method, when injecting the improved material into one drilled hole 110, any of the above-mentioned [6], [7], and [9] is performed regarding the injection of the improved material for each step. When this step was reached, the injection of improvement material at that step was completed and the step moved to the step above it. Then, the injection of the improving material was repeated for each step, and when the above-mentioned step [10] was reached, the work of injecting the improving material into the hole 110 was completed, leaving the uninjected step. In addition, the improvement material injection work was carried out sequentially for each drilled hole 110, and when the above-mentioned [8] was reached, the work was completed leaving the drilled holes 110 that had not been injected. Therefore, ground improvement work could not be carried out as planned.

In this regard, according to the static press-in compaction method of the present embodiment, it is possible to predict the total upheaval LT1 in the ground and proceed with the ground improvement construction in a manner that deals with this. Ground improvement work can be carried out as planned without leaving unfilled holes 110.

FIG. 12A shows a schematic configuration of a screen device 200 that can be incorporated into the construction system 100. FIG. 12A is a sectional view of the screen device 200 placed on the upper frame 201a of the pedestal 201. FIG. FIG. 12C is a side view of the screen device 200.

Large-diameter foreign objects such as gravel may be mixed into the sand in the improved material during the process of manufacturing, transportation, temporary storage, and kneading in the improved material production plant 105. Furthermore, the mortar adhering to the mixer of the improvement material production plant 105 may peel off and be mixed into the improvement material. If large diameter foreign matter (gravel, mortar attached to the improved material generation plant 105, etc.) gets mixed into the improved material, it will cause blockage in the pressure feed hoses 107 and 108 because the inner diameter of the pressure feed hoses 107 and 108 is as small as φ50 mm. There was a risk.

Therefore, in the construction system 100, it is preferable to pass the improvement material through the screen device 200 to remove the above-mentioned foreign substances.

The screen device 200 is placed on a pedestal 201 provided on the hopper 104a of the improved material pressure pump 104. The pedestal 201 includes an upper frame 201a that is rectangular in plan view, and a total of four legs 201b located at the four corners of the upper frame 201a. The upper frame 201a is constructed by assembling angle iron into a rectangular shape, for example.

The screen device 200 includes a frame body 202 that is rectangular in plan view, a rubber plate 203 provided on the lower surface of the rectangular frame body 202, and a bag-shaped bag-like opening on the top surface attached to the inner circumferential side of the frame body 202. It is configured by a net 204. The net 204 is made of, for example, a wire mesh having a mesh size of -20 mm. The lower end of the net 204 has a downwardly convex curved shape (see FIGS. 12(a) and (b)), and the lower end has a slight slope as shown in FIG. 12(c). have

A frame 202 of the screen device 200 is placed on an upper frame 201a of a pedestal 201 via a rubber plate 203. The net 204 of the screen device 200 is located within the opening of the upper frame 201a in plan view. The top opening of the net 204 of the screen device 200 is located directly below the discharge port 106a of the auger mixer 106.

A vibrator 205 is provided in the frame 202 of the screen device 200, and vibrations from the vibrator 205 are transmitted to the net 204. The vibrator 205 is, for example, a mold vibrator, but is not limited thereto.

The improved material is put into one side (shallow side) of the net 204 and falls into the hopper 104a due to the vibration caused by the vibrator 205 of the screen device 200, and foreign objects larger than 20 mm are thrown into the other end (deep side) of the net 204. They come together. This foreign material is removed as appropriate.

FIG. 13(A) shows a first modification of the screen device 200. In this modification, a foreign matter reservoir 207 is provided on the deep side of the net 204.

FIG. 13(a) shows a second modification of the screen device 200. In this modification, a foreign matter discharge pipe 208 is provided on the deep side of the net 204.

FIG. 14 is a top view of a third modification of the screen device 200. In this modification, a rectangular and planar wire mesh 211 is created around which a stopper 210 made of L-shaped steel or the like is attached, and this is attached onto the pedestal 201 via the above-mentioned rubber plate 203. At the time of this attachment, the planar wire mesh 211 is made to be inclined with respect to the horizontal plane (the wire mesh 211 is inclined in the diagonal direction), and the lowest part thereof is used as a foreign matter reservoir 212. Vibration from the vibrator 205 is also transmitted to this planar wire mesh 211.

By incorporating the screen device 200 into the construction system 100, it is possible to prevent the pressure feed hoses 107 and 108 from being blocked by foreign matter. In addition, the vibration by the vibrator 205 allows the improving material (hardened mortar with a slump value of 5 cm or less) to pass smoothly through the mesh of the screen device 200. Furthermore, foreign matter rejected by the screen device 200 can be easily removed from the screen device 200.

According to the present embodiment, the compaction method in which the surrounding ground is compressed and compacted by creating the improved body 150 by injecting the improving material into a plurality of drilled holes 110 formed in the ground is The first step (step S1) is to obtain the planar distribution of the amount of ground upheaval caused by injecting the improvement material into the holes 110. Assuming that the planar distribution of the amount of uplift of the ground obtained in step S1) occurs, the second step (step S2) of calculating the total uplift amount LT1 of the ground, and the second step (step S2) A third step (step S3) is included in which the calculated total uplift amount LT1 is compared with a predetermined value (upper limit value LT0 of the total uplift amount). In the third step (step S3), when the total upheaval amount LT1 exceeds a predetermined value (upper limit value LT0 of the total upheaval amount), improving material is added to one drilled hole 110 so as to reduce the total upheaval amount LT1. The construction control value at the time of injection and/or the injection method of the improvement material is changed (step S4). As a result, it is possible to predict the total amount of upheaval LT1 in the ground and proceed with the construction in a manner that deals with this, making it possible to manage the amount of uplift of the ground more easily than in the past.

Further, according to the present embodiment, the construction management value is the upper limit value SM of the amount of ground upheaval for each step when injecting the improvement material into one borehole 110, and It includes at least one of an upper limit value TM of the total amount of elevation of the ground, an upper limit value PM of the injection pressure of the improvement material, and a target value GT of the proportion (injection rate) of the improvement material in the ground. This construction management value can be changed in step S4 described above.

Further, according to the present embodiment, changing the injection method in step S4 includes at least one of the following (a) to (c).
(A) Changing the order in which a plurality of improved bodies 150 are created by injecting the improving material into one drilled hole 110.
(b) The pump for injecting the improved material (improved material pressure pump 104) is used to inject the improved material while repeating loading and unloading of the improved material. change the operating mode of the
(c) For adjacent drilling holes 110, increase the time interval between times when improving material is injected.
By performing at least one of these, it is possible to reduce the amount of upheaval of the ground.

Further, according to the present embodiment, in the first step (step S1), the planar distribution of the amount of upheaval of the ground caused by the injection of the improvement material into one borehole 110 is measured by testing the improvement material in one borehole 110. Obtained by injection (test construction) or by numerical analysis. This acquired data can be utilized for predicting the total amount of upheaval LT1 in the ground. In addition, in the compaction method according to this embodiment, the construction control values set prior to step S1 and/or the injection method of the improvement material may be reviewed according to the results of this test injection or the results of numerical analysis. May include.

Further, according to the present embodiment, the improved material includes hardened mortar having a slump value of 5 cm or less. By constructing the improved body 150 using such an improved material with extremely low fluidity, the surrounding ground can be compressed and strengthened.

Note that when this embodiment is applied to the SAVE construction method, a special polymer may be used instead of cement as a solidifying material constituting the improvement material.

The illustrated embodiments are merely illustrative of the present invention, and the present invention covers various improvements and changes that may be made by those skilled in the art within the scope of the claims, in addition to what is directly shown by the described embodiments. Needless to say, it is inclusive.

100 Construction system 101 Injection pipe 103 Flow rate pressure monitoring device 104 Improved material pressure pump 104a Hopper 105 Improved material generation plant 106 Auger mixer 106a Discharge port 107, 108 Pressure feed hose 110 Drilled holes 150 Improved body 200 Screen device 201 Frame 201a Upper frame 201b Legs 202 Frame 203 Rubber plate 204 Net 205 Vibrator 207 Foreign matter reservoir 208 Foreign matter discharge pipe 210 Stopper 211 Wire mesh 212 Foreign matter reservoir

Claims (5)

A compaction method that compresses and compacts the surrounding ground by creating an improved body by injecting improving material into multiple boreholes formed in the ground,
A first step of obtaining a planar distribution of the amount of ground upheaval caused by injection of improvement material into one borehole;
A second step of calculating the total amount of upheaval in the ground, assuming that the planar distribution of the amount of uplift in the ground obtained in the first step occurs with respect to each of the plurality of boreholes, due to the injection of the improvement material. process and
a third step of comparing the total upheaval amount calculated in the second step with a predetermined value;
including;
In the third step, when the total upheaval amount exceeds the predetermined value, the construction control value and/or improvement at the time of injecting the improvement material into one drilling hole is determined so as to reduce the total upheaval amount. A compaction method that changes the method of material injection. The construction control value includes an upper limit of the amount of elevation of the ground for each step when injecting the improvement material into one borehole, an upper limit of the total amount of elevation of the ground when injecting the improvement material into one borehole, The compaction method according to claim 1, comprising at least one of an upper limit value of the injection pressure of the improvement material and a target value of the ratio of the improvement material in the ground. According to claim 1 or 2, in the first step, the planar distribution is obtained by test injecting the improvement material into one drilled hole, or the planar distribution is obtained by numerical analysis. Compaction method. The compaction method according to claim 3, comprising reviewing the construction control value and/or the injection method according to the result of the test injection or the result of the numerical analysis. The compaction method according to any one of claims 1 to 4, wherein the improved material includes hardened mortar having a slump value of 5 cm or less.