JP3462702B2 - Method of forming underground continuous wall - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an underground continuous wall formed by stirring and mixing a liquid for consolidation such as cement milk and earth and sand in situ. For the method. 2. Description of the Related Art Conventionally, a ground has been excavated while a liquid for consolidation such as cement milk is being injected, and the liquid for consolidation and the excavated in-situ earth and sand have been stirred and mixed. Forming a continuous wall is performed. In this case, a multi-axis excavator,
For example, while excavating the ground using a three-axis multi-screw excavator, the consolidation liquid and the in-situ earth and sand are stirred and mixed to form leading holes at intervals, and then the consolidation liquid is formed. Excavate the unexcavated ground between the preceding holes while pouring, mix with the in-situ earth and sand to form the following hole, and partially overlap the end of the following hole with the end of the preceding hole in plan view. Thereby, the underground continuous wall is formed by forming a continuous hole in which the preceding hole and the following hole partially overlap in plan view. However, the time elapses between the formation of the leading hole at a certain interval and the formation of the trailing hole, the curing proceeds in the leading hole, and the end of the trailing hole is moved to the end of the leading hole. When inserting the core material etc. after partially overlapping the part in plan view, the workability of inserting the core material into the preceding hole part because the leading hole part begins to harden faster than the following hole part Is bad,
There has been a problem that the core material cannot be inserted to the required depth (the core material stays high). [0004] Therefore, it is conceivable to increase the water-cement ratio by increasing the amount of water to increase the fluidity of the liquid for consolidation used in forming the preceding hole, but this would reduce the strength. In addition, since the injection amount is large, the amount of the consolidating liquid discharged to the ground is large, which increases the cost of mud disposal, and furthermore, the cement disposed of as mud is also wasted. There was a problem that the amount of total cement used also increased. SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and can easily insert a core material while maintaining the fluidity of a preceding hole. In addition, the amount of water and the amount of pouring are also reduced, the amount of mud generated is reduced, and the underground continuous wall which can form a high quality underground continuous wall with uniform quality in the lateral direction without lowering the quality. It is an object of the present invention to provide a method for forming a film. In order to solve the above-mentioned problems, a method of forming an underground continuous wall according to the present invention comprises: The pre-holes 2 are formed at intervals by stirring and mixing the soil and sand at the position, and then the unexcavated ground 6 between the pre-holes 2 is excavated while the liquid for consolidation without adding a dispersant is injected. The trailing hole 3 is formed by stirring and mixing with the earth and sand at the position, and the end of the trailing hole 3 partially overlaps the end of the leading hole 2 in plan view, so that the leading hole 2 and the trailing hole 3 are continuous. A continuous hole 9 is formed. By adopting such a method, the liquid for consolidation to which the dispersant is added and the in-situ earth and sand are agitated and mixed in the preceding hole 2, and the fluidity of the preceding hole 2 is improved by the flowability of the dispersant. At the stage where the trailing hole 3 is formed, the same fluidity as that of the trailing hole 3 can be obtained.
In the overlapping portion between the end of the leading hole 2 and the end of the leading hole 2, good and uniform stirring can be performed, and the end of the leading hole 2 and the end of the trailing hole 3 partially overlap in plan view. When the core material 4 is inserted into the leading hole 2 portion and the trailing hole 3 portion after being formed, the core material 4 can be smoothly inserted in any case. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments shown in the accompanying drawings. First, as shown in FIG. 1, the ground 1 is excavated by the multi-axial excavator 10 to form the preceding hole 2. In this case, when excavating by the multi-axial excavator 10, the multi-axial excavator 10 A consolidation liquid such as cement milk to which a dispersant is added is injected into the ground through an injection hole (not shown) provided, and a consolidation liquid such as cement milk to which this dispersant is added. The object and the excavated earth and sand at the original position are stirred and mixed by the stirring means 5 provided in the multi-screw excavator 10. In the embodiment shown in the accompanying drawings, the multi-axis excavator 10 is an example of a three-axis excavator, and three holes are continuously formed in a state where the holes partially overlap each other in plan view. Similarly, as shown in FIG. 2, other preceding holes 2 are formed at regular intervals. Here, the distance L ₁ between the center of the hole at one end of the preceding hole 2 and the center of one end of the adjacent preceding hole 2 is equal to the distance of the leading hole 2.
It is equal to the distance L ₂ between the centers of both end portions of the holes of.
The preceding holes 2 are formed one after another at regular intervals as described above. In addition, as a dispersing agent, for example, “Geospar K (trade name, manufactured by FPC Inc.)” can be used. After a large number of preceding holes 2 are formed at regular intervals as described above, the unexcavated ground 6 between the preceding holes 2 is excavated by the multiaxial excavator 10 to form the trailing holes 3. In this case, when excavating the multi-axis excavator 10, the multi-axis excavator 1
A liquid for consolidation, such as cement milk, to which no dispersant is added, is injected into the ground through an injection hole provided at 0, and a liquid for consolidation, such as cement milk, and excavated earth and sand excavated from the undigged ground 6 Are mixed with stirring. In this case, the excavating shafts 10a located at both ends of the multi-screw excavator 10 are respectively inserted into the holes at the ends of the adjacent preceding holes 2, and the excavating shafts positioned at the center of the multi-screw excavator 10 while using these as guides. 10a, the unexcavated ground 6 between the preceding holes 2 is excavated as shown in FIG. 3, but at the same time, a mixture of the liquid for consolidation and the excavated earth and sand excavated from the unexcavated ground 6, and the adjacent preceding hole The mixture of the liquid for consolidation to which the dispersant added in the hole at the end of the hole 2 and the excavated earth and sand in situ are further stirred and mixed, and the filler A in the preceding hole 2 and the subsequent The filler B in the hole 3 is stirred and mixed in a uniform state. In the above process, the filler A filled in the preceding hole 2 is filled with a liquid for consolidation such as cement milk to which a dispersant is added, and is stirred and mixed with the in-situ earth and sand. Therefore, even if a long time passes between the formation of the large number of leading holes 2, since the flowability is increased by the dispersant and the curing is delayed, the filler filled in the trailing holes 3 B can exhibit substantially the same degree of fluidity as that of B, and therefore can exhibit the same fluidity even in a part of the ends of the leading hole 2 and the trailing hole 3 that partially overlap in plan view. As a result, after the end of the leading hole 2 and the end of the trailing hole 3 are formed so as to partially overlap in plan view as described above, the core 4 is inserted as shown in FIG. When inserting and inserting the core material 4, the leading hole 2, the trailing hole 3, and the end of the leading hole 2 partially overlap with the end of the trailing hole 3 in plan view. Since the same degree of fluidity is exhibited in any of the portions, the core material 4 can be smoothly inserted and built. As described above, the continuous hole 9 is formed such that the ends of the leading hole 2 and the trailing hole 3 partially overlap each other, and the core material 4 is obtained by curing the filler. Underground continuous walls can be formed. According to the present invention, as described above, while excavating the ground, the liquid for consolidation to which the dispersant has been added and the in-situ earth and sand are stirred and mixed to form the preceding hole. Formed at intervals, and then, while injecting the liquid for consolidation without adding a dispersant, excavating the undigged ground between the preceding holes and stirring and mixing with the in-situ earth and sand to form the trailing holes Since the end of the trailing hole partially overlaps the end of the leading hole in plan view to form a continuous hole in which the leading hole and the trailing hole are continuous, in forming the leading hole, the amount of water used is reduced. Even after the fluidizing action of the dispersant increases the fluidization of the filler filled in the preceding hole and delays curing, thereby forming the trailing hole,
When inserting and embedding the core material, the leading hole portion, the trailing hole portion, any part of the portion where the end of the leading hole and the end of the trailing hole partially overlap in plan view Having the same degree of fluidity, it is possible to insert and insert the core material smoothly, and as in the past, hardening progresses in the preceding hole part and it is difficult to insert the core material. The phenomenon that the core material does not stay high does not occur, and in increasing the fluidity of the preceding hole, the amount of water is not increased by increasing the amount of water, so the amount of water can be reduced,
It does not cause a decrease in strength, and in forming the preceding hole, the injection amount of the liquid for consolidation can be reduced, and the amount of generated mud overflowing on the ground can be reduced. In addition to reducing the amount of waste, the amount of waste cement discarded in the material to be disposed of as mud can be reduced, which can also reduce costs, and the filling in the preceding hole progresses hardening. Because it does not partially overlap with the end of the trailing hole at the stage before being stirred and mixed,
The quality of the formed underground continuous wall can be made substantially equal in the lateral direction, and a high-quality underground continuous wall can be formed.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 (a) is a front sectional view showing a construction order in one embodiment of the present invention, and FIG. 1 (b) is a plan sectional view. FIG. 2 (a) is a front sectional view showing a construction order according to the embodiment, and FIG. 2 (b) is a plan sectional view. FIG. 3 (a) is a front sectional view showing a construction order according to the embodiment, and FIG. 3 (b) is a plan sectional view. FIG. 4 (a) is a front sectional view showing the same working order as in the above, and FIG. 4 (b) is a plan sectional view. [Description of Signs] 1 Ground 2 Leading hole 3 Trailing hole 4 Core material

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) E02D 3/12 E02D 5/18

Claims (1)

(57) [Claims 1] While excavating the ground, a liquid for consolidation to which a dispersant is added and earth and sand in situ are stirred and mixed to form leading holes at intervals. After that, the unexcavated ground between the preceding holes is excavated while pouring the liquid for consolidation without adding a dispersant, and is stirred and mixed with the in-situ earth and sand to form the following holes and ends of the following holes. Wherein the end of the leading hole partially overlaps in plan view to form a continuous hole in which the leading hole and the trailing hole are continuous.