JP4236119B2 - Construction method of mountain retaining wall - Google Patents

Description

  The present invention relates to a construction method of a retaining wall that prevents the surroundings of a hole dug in the ground from collapsing in construction or civil engineering work.

  Conventionally, the construction method of the retaining wall that has been generally adopted employs a main pile horizontal sheet pile method using H-shaped steel and a wooden horizontal sheet pile as a parent pile, and a soil column array method.

  As shown in Fig. 6, the former parent pile side sheet pile method is prepared with a length of parent pile 1 that is the depth from the ground to the root cutting base plus the root insertion length, and wooden side sheet pile 2, and the auger Using a machine, the master pile 1 is driven into the ground at a pre-calculated interval, and the upper ends of the parent piles 1 are joined by the head joints 3, and as the ground excavation work (root cutting) proceeds, the parent pile 1 and the main pile 1 are fitted with a horizontal sheet pile 2 one after another, and a mountain retaining wall 4 is constructed by continuing this until reaching the root cutting bottom. It prevents the ground from collapsing.

  Also, the latter soil column method uses a single-axis or multi-axis auger machine. In the case of a single-axis auger machine, the inside of the vertical hole drilled from the ground surface to the root is made with soil cement and the main pile is Embedding and constructing such parent piles at planned intervals, and then constructing a soil cement wall between the parent piles.

  When using a multi-axis auger machine, not only the vertical hole into which the main pile is inserted, but also all vertical holes are used as soil cement walls to the bottom.

  By the way, the former parent pile horizontal sheet pile method is a low cost method, but has the following problems.

(1) Since the horizontal sheet piles 2 are sequentially fitted between the main pile 1 and the main pile 1, a gap is generated between the upper and lower horizontal sheet piles 2 and there is no waterstop as the retaining wall 4, so spring water from the non-excavation side ground If this occurs, it will interfere with the excavation work by flowing into the excavation part.

(2) When the side sheet pile 2 is fitted, it is difficult to sufficiently fill the back side of the side sheet pile 2 with soil, and the movement of the back soil and the settlement of the non-excavation side ground are likely to occur.

(3) The work for fitting the horizontal sheet pile 2 takes time, and the work efficiency is poor.

(4) When the actual ground condition is worse than the ground condition assumed at the time of the survey, the lateral sheet pile 2 may not enter.

(5) If there is movement of the back soil or subsidence of the non-excavation side ground, there is a high possibility that the surrounding area will be adversely affected, especially when there is a neighboring house near the back side or when the ground is soft.

  In addition, the latter soil column method has the following problems.

(A) When a main pile and a soil cement wall are constructed using a single-axis auger machine, the construction takes time and the efficiency is poor.

(B) It is easy to produce a defect in the construction of the lap part of the soil cement in the construction of the parent pile and the soil cement wall, and it is difficult to appropriately withstand earth pressure and water pressure as a retaining wall.

(C) When using a multi-axis auger machine, since not only the vertical hole into which the main pile is inserted but also all vertical holes are used as soil cement walls to the bottom, the use of cement is wasteful.

  Therefore, in order to solve the above-described problems, the object of the present invention is to construct a mountain retaining wall having an appropriate water-stopping property by constructing a mountain retaining wall with a soil cement wall instead of a wooden cross sheet pile. It is another object of the present invention to provide a method for constructing a retaining wall that can move back soil and subsidize non-excavated ground, improve work efficiency, save labor, and reduce the amount of cement used.

  In order to solve the above-described problems, the present invention uses a triple auger device in which the central auger is longer than the augers on both sides, and the triple vertical hole having a deep vertical hole in the center and a shallow vertical hole on both sides is provided. Drilling and supplying cement milk at the time of excavation of this triple vertical hole to make the inside of the triple vertical hole like soil cement, after extracting the auger device, embedding a main pile in the central deep vertical hole to form a unit wall The unit wall is constructed so that shallow vertical holes overlap each other, thereby adopting a configuration in which a continuous retaining wall is constructed with solid cement cement of each unit wall.

  In the triple auger device described above, the central auger is set to the depth from the ground to the root cutting bottom plus the base pile length, and the augers on both sides are deep from the ground to the root cutting bottom. The length of the central auger is set so as to match the length, and the cement milk is discharged from the head at the tip, and the cement milk and the excavated soil are mixed with stirring.

  In addition, the short auger heads on both sides can be configured such that the maximum diameter portion at the upper end is formed in a ring structure to prevent the occurrence of breakage or the like due to contact with the parent pile embedded earlier.

  Here, the central auger has different rooting length depending on conditions such as excavation depth and ground properties, so various augers with different lengths are combined to make the required length, and the short augers on both sides are also Since it differs depending on the excavation depth of the ground and the building, the required length is set in the same manner as described above.

  Also, the short auger heads on both sides prevent the occurrence of breakage due to contact with the main pile embedded in the vertical hole of the unit wall previously constructed when constructing the unit wall so that the shallow vertical holes overlap. Therefore, the maximum diameter portion at the upper end of the central axis has a ring structure.

  According to the present invention, a triple auger device is used to excavate a triple vertical hole having a deep vertical hole at the center and a shallow vertical hole on both sides, and the parent pile is placed in the deep vertical hole at the center of the triple vertical hole. By embedding and forming unit walls of soil cement, and constructing the unit walls in such a way that shallow vertical holes overlap each other, we constructed a retaining wall by continuation of each unit wall, so instead of wooden side sheet piles Therefore, it is possible to build a water retaining wall with a soil cement wall, which prevents the spring water from the non-excavation side ground from flowing into the excavation part, and excavation work with the spring water from the non-excavation side ground Can be prevented.

  In addition, by constructing a retaining wall with soil cement wall directly on the ground, there is no movement of the back soil or settlement of the non-excavation side ground, and there is a neighboring house near the back side or when the ground is soft In addition, excavation can be performed without adversely affecting the surrounding area.

  In addition, since the retaining wall is built directly on the ground with soil cement walls, the work efficiency and labor saving can be improved, and only the vertical hole into which the main pile is inserted has a depth to the root, and the vertical holes on both sides are rooted. Since a shallow depth to the bottom is sufficient, the amount of cement used can be reduced.

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

  As shown in FIG. 1, a triple auger device 11 for excavating a triple vertical hole is provided with a long central auger 13 and short augers 14 located on both sides thereof at the lower part of a casing 12 housing a speed reduction mechanism. Each auger 13, 14 is driven to rotate by a motor 15 above 12.

  The central long auger 13 has a length obtained by adding the root insertion length to the depth from the ground to the root cutting bottom, and the augers 14 on both sides have the excavation length from the ground to the root cutting bottom. , 14 are provided with excavation heads 16 and 17 at their respective tips, and the head 16 of the long auger 13 has a discharge port 13a for discharging cement milk supplied from the upper end of the auger 13 through the shaft, Each auger 13 and 14 is made to agitate and mix cement milk and excavated soil during rotation by means of a suitable agitating blade 18 provided at the shaft portion.

  The cement milk is discharged only by the central long auger 13, but the cement milk discharged from the central long auger 13 gradually rises upward as the drilling progresses. The portion of the hole drilled by the auger 14 is filled.

  As shown in FIG. 2, the triple auger device 11 excavates a triple vertical hole 21 having a deep vertical hole 19 at the center and a shallow vertical hole 20 on both sides with respect to the ground. Cement milk is supplied at the time of excavation so that the inside of the triple vertical hole 21 is made into a soil cement shape. After the auger device 11 is extracted, a main pile 22 using H-shaped steel is embedded in the deep vertical hole 19 at the center, and the unit wall 23 is formed. Form.

  As shown in FIG. 4, by arranging the unit walls 23 so that the shallow vertical holes 20 overlap each other, it is possible to construct the retaining wall 24 that is continuous with the solid cement cement of each unit wall 23.

  The above-mentioned central auger 13 has different depth depending on conditions such as the depth of excavation and the properties of the ground. Therefore, various augers having different lengths are combined to make a necessary length. Since it differs depending on the excavation depth of the ground and the building, the required length is set in the same manner as described above.

  Further, as shown in FIGS. 1B and 1C, the heads 17 of the short augers 14 on both sides are arranged so that when the unit walls 23 are arranged side by side so that the shallow vertical holes 20 overlap, In order to prevent the occurrence of damage or the like due to contact with the main pile 22 embedded in the deep vertical hole 19, a ring plate 26 with a face is provided at the upper end portion of the central shaft 25 in a coaxial arrangement. A plurality of stirring blades 27 with cutting blades are projected in a radial arrangement.

  As a result, when excavating the triple vertical hole 21, when the shallow vertical hole 20 is constructed in a wrap shape, the rotation of the short auger 14 can be maintained even if the ring plate 26 may come into contact with the parent pile 22. Since there is no trouble caused by collision with the parent pile 22 and the lap construction of the shallow vertical hole 20 can be surely performed, the soil cement is connected, and the retaining wall 24 that can withstand earth pressure and water pressure can be constructed.

  Next, a method for constructing a retaining wall using the triple auger device will be described.

  As shown in FIG. 1 (a), the central auger 13 in the triple auger device 11 has a length obtained by adding the rooting length to the depth from the ground to the root cutting bottom, and the augers 14 on both sides are rooted from the ground. With the excavation length to the bottom, as shown in the process diagram of FIGS. 2 (a) to 2 (e), arrange the three auger devices 11 attached to the pile driver vertically to the position where you want to construct the retaining wall. While the augers 13 and 14 are rotated by the start of the motor 15, first, the longitudinal holes 19 are excavated to the bottom of the root with the long central auger 13, and then the main auger 13 and the augers 14 on both sides are respectively parent pile roots. The triple vertical hole 21 is excavated by excavating the vertical hole 20 between the insertion portion and the parent pile.

  At the time of excavation of the vertical holes 19 and 20 by the augers 13 and 14, cement milk (cement-based suspension composed of cement + bentonite + water + admixture) from the discharge port 13a provided at the tip head 16 of the central auger 13 After mixing with soil with a stirring blade 18, the inside of the triple vertical hole 21 is made into a soil cement shape, the triple vertical hole 21 having a predetermined depth is excavated, and the auger device 11 is extracted. The unit wall 23 is formed by embedding a parent pile 22 using H-shaped steel in the deep vertical hole 19 at the center.

  Incidentally, the central auger 13 in the triple auger device 11 has an excavation diameter of 550 mm or more, the augers 14 on both sides have an excavation diameter of 550 mm, and the distance between the central auger 13 and both augers 14 is 450 mm. The triple vertical hole 21 can be excavated by setting the deep vertical hole 19 excavated by the central auger 13 and the shallow vertical hole 20 excavated by the augers 14 on both sides partially overlapping in plan view. It has become.

  Next, as shown in FIGS. 3 (f) and 3 (g), the triple vertical holes 21 are arranged side by side so that the shallow vertical holes 20 overlap each other between the triple vertical holes 21 as described above. As shown in FIG. 4, a continuous retaining wall 24 can be constructed by solidified soil cement of each unit wall 23, and the upper half of the shallow vertical hole 20 and the long vertical hole 19 has a depth to the root cutting bottom. This is a soil cement mountain retaining wall 24, and the lower half of the long vertical hole 19 is a root portion for supporting the parent pile 22.

  Here, in the construction of the unit wall 23 by the triple vertical hole 21, the interval between the parent piles 22 is about 900 mm to about 1200 mm depending on the construction conditions, the auger diameters of the augers 13 and 14 are 550 mm, and the augers 13 and 14. Several construction orders can be employed under the condition that the interval of 450 mm is 450 mm.

  FIG. 5 (a) is an example of construction when the interval W between the main piles is 900 mm. As the preceding construction shown in the upper part of the figure, the unit walls 23 formed by the triple vertical holes 21 and the main pile 22 are spaced at a pitch of 1800 mm. Next, the unit wall 23 is constructed by the triple vertical holes 21 and the main pile 22 between the adjacent unit walls 23 as a subsequent construction indicated by a one-dot chain line in the middle of the figure.

  In the subsequent construction, the shallow vertical holes 20 on both sides just overlap with the shallow vertical holes 20 in the preceding construction, and the augers 14 on both sides only need to knead the previous soil cement. As shown in the lower part of (a), a continuous mountain retaining wall 24 in which the distance between the parent piles 22 becomes 900 mm with soil cement is completed.

  In addition, as for the combination of preceding construction and subsequent construction, an arbitrary order can be adopted in addition to the construction order as shown by the numbers in FIGS.

  FIG.5 (b) is an example of construction in the case where the interval between the main piles 22 is 1000 mm, and the unit walls 23 by the triple vertical holes 21 are arranged intermittently at a pitch of 2000 mm as the preceding construction shown in the upper part of the figure. Next, the unit walls 23 are formed by the triple vertical holes 21 between the adjacent unit walls 23 as a subsequent construction indicated by a one-dot chain line in the middle of the figure.

  In the subsequent construction, the shallow vertical holes 20 on both sides overlap with the shallow vertical holes 20 in the preceding construction in a slightly misaligned state, and the augers 14 on both sides perform less excavation and kneading of the soil cement to complete the subsequent construction. For example, as shown in the lower part of the figure, a continuous mountain retaining wall 24 in which the distance between the main piles 22 is 1000 mm is completed with soil cement.

  FIG.5 (c) is an example of construction when the distance between the main piles 22 is 1200 mm, and the unit walls 23 by the triple vertical holes 21 are arranged intermittently at a pitch of 2400 mm as the preceding construction shown in the upper part of the figure. Next, the unit walls 23 are formed by the triple vertical holes 21 between the adjacent unit walls 23 as a subsequent construction indicated by a one-dot chain line in the middle of the figure.

  In the subsequent construction, the shallow vertical holes 20 on both sides overlap with the shallow vertical holes 20 in the preceding construction in a misaligned state, and the augers 14 on both sides perform less excavation and kneading of soil cement, as shown in the lower part of the figure. When the subsequent construction is completed, a continuous mountain retaining wall 24 in which the distance between the parent piles 22 becomes 1200 mm with soil cement is completed.

  As for the retaining wall 24 constructed in this way, the upper half of the deep vertical hole 19 into which the parent pile 22 is inserted and the shallow vertical hole 20 have a height from the ground surface to the excavation bottom, and the parent pile 22 is inserted. The lower half portion of the deep vertical hole 19 becomes a rooted portion, which prevents a collapse of the non-excavation side ground outside the building and becomes a retaining wall 24 that can withstand earth pressure and water pressure.

(A) is a front view showing a triple auger device, (b) is an enlarged front view showing a short auger head, and (c) is a cross-sectional plan view of the same. (A) thru | or (e) are process drawings of the first half which show the construction process of the unit wall by a triple vertical hole in order. (F) thru | or (g) are process drawings of the latter half which show the construction process of the unit wall by a triple vertical hole in order. (A) is a partially cut front view of the constructed retaining wall, (b) is an enlarged cross-sectional plan view along arrow aa in (a). (A) thru | or (c) is a top view which shows the example from which the pitch of a parent pile differs, and the example of the construction order of the unit wall by a triple vertical hole, respectively The perspective view which shows the parent pile side sheet pile method which is the conventional retaining wall

Explanation of symbols

11 Triple auger device 12 Casing 13 Center long auger 13a Discharge port 14 Short auger 15 Motors 16 and 17 Drilling head 18 Stirring blade 19 Deep vertical hole 20 Shallow vertical hole 21 Triple vertical hole 22 Parent pile 23 Unit wall 24 Mount Wall 25 Central shaft 26 Ring plate 27 Stirring blade with cutting blade

Claims (1)

  Using a triple auger device (11) in which the central auger (13) is longer than the augers (14, 14) on both sides, the central auger device (11) is a deep vertical hole (19) and both sides are shallow vertical holes (20, 20). Excavating the triple vertical hole (21), when excavating the triple vertical hole (21), while discharging the cement milk only from the discharge port (13a) of the head (16) of the central auger (13), The cement milk and excavated soil are agitated and mixed by the stirring blade (18) of the shaft portion of the central auger (13), and the discharged cement milk rises and the augers (14, 14) The inside of the triple vertical hole (21) is made into a soil cement shape by being stirred by the stirring blade (18) of the shaft portion, and the inside of the deep vertical hole (19) in the center after the auger device (11) is extracted. Unit with parent pile (22) embedded in By forming the unit wall (23) and arranging the unit walls (23) so that the shallow vertical holes (20) overlap with each other, the mountain retaining wall (24) continuous with the solidified soil cement of each unit wall (23) is formed. Construction method of the retaining wall to be constructed.

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