JPS59224725A - Sheathing work - Google Patents

Abstract

PURPOSE:To prevent the deformation of the ground by a method in which cement-based powdery granules are packed into a cylindrical casing penetrated into the ground, and the casing is pulled out while discharging the powdery granules downwards to form continuous piles in order. CONSTITUTION:While being turned, a cylindrical casing 1 is penetrated into the ground, and cement-based powdery granules 3 having water absorbability, expandability, and hydraulically setting property are packed into the casing 1. A screw 4 is turned or compressed air is supplied, and the casing 1 is pulled up to form a pile 6. Other piles 6 are orderly formed connectedly to the existing pile 6 to form a sheathing cut-off wall 7.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an earth retaining method for excavation work when constructing a relatively small-scale underground structure. This construction method makes it possible to completely prevent the effects of

Conventionally, as this type of earth retaining method, steel sheet pile method, column row earth retaining wall method, soil cement pile earth retaining wall method, etc. are known.

By the way, in the steel sheet pile construction method, ``directly driving the steel sheet piles causes noise problems in urban areas, so normally the area where the steel sheet piles are to be placed is first drilled with an auger and cement milk is poured in.'' The method used is to install steel sheet piles after the steel sheet piles have been removed.

However, with this construction method, it is inevitable that the surrounding ground will loosen until the poured cement milk hardens, and the surrounding ground will become unstable after the poured steel sheet piles are recovered. There is.

Similarly, the pillar row earth retaining wall construction method and the soil cement pile wall construction method also have the disadvantage that the surrounding ground is unavoidably loosened until the cement milk hardens during construction.

The present invention was made with a focus on these 11 towns, and its purpose is to make it possible to install ±f1j walls without the inconvenience caused by loosening of the surrounding ground, and to prevent slippage. It is famous for providing an earth retaining method that can reliably prevent destruction and deformation due to loosening of the soil behind the earth wall.

The present invention will be explained below.

The earth retaining method according to the present invention includes press-fitting a cylindrical casing to a predetermined depth, filling the casing with a cement-based granular material having water absorption, expandability, and hydraulic properties, and Do not release the material downward]) IJ
The required number of piles are brought into close contact with each other by punching out the cement casing and forming piles of the cementitious powder material. It comprises a material component, an expandable phase component having expandability, and an aggregate component having water permeability.

As cementitious material components having hydration hardening properties, for example, gypsum, Ryoro slag, and ordinary Portland cement may be used as main ingredients, and halogen compounds or sulfates may be added as hardening accelerators as necessary. A solidifying agent is mixed, Osaka ESC! (Product name: Osaka Cement Co., Ltd.). This assimilator has a mixing ratio of gypsum, blast furnace slag, and ordinary Portland cement, which are the main materials, to 15 to 60 (weight%) of gypsum,
Blast furnace slag 20 to 60 (weight%) and ordinary Portland cement 10 to 50 (M, weight %) are ground and mixed so that the specific surface area is 4,5 o arm"7 g or less, or, It is made by adding 5 (wt%) or less of a curing accelerator to these, pulverizing and blending them, and has water absorption, swelling properties, and hydraulic properties.In addition, as an expanding material component having swelling properties, For example, there are quicklime and expansive cement.This component serves to further increase the expansion effect.The water-permeable aggregate component includes, for example, blast furnace slag, dry slag, or dry sand. This component plays a role in assisting water utilization to reach the center of the pile, but dry blast furnace slag can contribute to long-term strength development more than dry sand. The mixing ratio of
20-50% cement-based material component, 20-50% aggregate component
50% expansion material component is 0 to 30%.

Part 1. The cement-based granular material is driven into the ground using the following method. That is, for example, as shown in Fig. 1(a), a 7400 to 500 mW cylindrical casing l with a conical tip is press-fitted into the ground 2 while rotating, and 7L; into this casing 1, the cement-based granular material 3 made by mixing the above-mentioned components in appropriate proportions is charged and filled. Thereafter, as shown in FIG. 1(C), the cement-based granular material 3 is inserted into the screw 4 disposed at the axial center of the casing l.
1 to 7 from the head of the casing 1.
By supplying and pressurizing the compressed air 5 of kg/'crll, and pulling the nuclear casing 1 with its bottom open upward while pushing it downward, it is made into a single tree as shown in Fig. 1(d)K. form a pie 1v6. Subsequently, by the same procedure, piles 6... are sequentially formed in a predetermined direction by overlapping the previous pile in the range of 100 WII+ or less, and the piles 6... are formed as shown in FIG. 1 (θ) by a group of these piles 6... Reinforce the earth retaining water stop wall 7 as shown below. Here, the term "steel material such as H-beam steel" refers to a steel material having a shape that fits within the casing 1 described above, and in which H-beam steel or reinforcing bars are assembled in an oily manner. The method for inserting the steel material is to set the steel material in the casing 1 in advance [2] and then press it into the ground 2, or to insert the steel material into the core caning 1 after the casing 1 has been press-fitted, and then fill the cement-based granular material 3. death,
This method involves pulling out only the casing.

In this case, the method for pulling out the casing is the compressed air method described above since it is impossible to use one screw method. Also, H
If the length of the shaped steel is 4 m or less, the pile 6 may be driven into the pile 6 using equal pressure with a pile driver after the pile 6 is driven. These series of construction processes are carried out without vibration and noise, and construction in urban areas is fully possible.

However, according to this more advanced earth retaining method, cement milk is not used as in the conventional method because the soil is formed from cement-based granular material that has water absorbency, expandability, and hydraulic properties. There is no inconvenience caused by the loosening of the surrounding ground, which would otherwise occur. Therefore, if the earth retaining wall is constructed using this construction method, it is possible to reliably prevent ground deformation on the back side of the earth retaining wall due to loosening K of the ground.

The construction conditions may vary depending on the soil conditions of the ground and excavation conditions, but generally speaking, in the case of soft soil conditions with a high water content ratio, a material with high strength is selected, Furthermore, if the excavation depth is large, the steel material will be reinforced as necessary, as described above. In addition, if you want to ensure the water-tightness of the earth retaining wall, it is desirable to select a material with high expansibility and to increase the overlap of the piles. In addition to the above-mentioned reinforcing steel materials, there is also a construction method in which unbonded PC steel rods or the like are used and tensioned and reinforced after hardening.

Examples of the present invention will be described below.

Example 1 Piles made of cement-based granular material of f; This pouring was carried out in three construction zones A, B, and C. A
, B and B construction areas have a cement-based material component of 45% consisting of the aforementioned Osaka ESC and an aggregate component of 45% consisting of blast furnace slag.
, piles made of cement-based granular material mixed with a 10% expansion phase component consisting of quicklime were installed, and in section C, a pile was constructed using a cement-based material component consisting of 40% Osaka EESC and blast furnace slag. Aggregate [component 40%,
A pile formed of a cement-based granular material containing 20% of the expansion j1 long-wall component made of quicklime and twice the mixing ratio of the expansion agent component was installed (Table 1). Then, in each of the above-mentioned sections A and B%C, 1.5% from the pile edge.
When the distance is 4 m, measure the lateral displacement of the ground using the inclinometer at the γ position.
([j was determined. The A'i result is, as shown in Figure 2,
The displacement ViC section was the largest, followed by sections A and B, but in both sections, the piles expanded and consolidated the surrounding ground, preventing the ground from loosening. Note that C' is the measured value of the amount of displacement at a position 0.85 m away from the pile edge in section C.

Table 1 Example 2 90c from steel sheet pile (SPW type) buried to a depth of 13m
In order to reach a depth of 13 m, piles were constructed of cement-based granular material using the construction method according to the present invention. The cement thread granule ladle used in this casting was made of Osaka ESC with a cementitious material component of 20
%, 50% of the aggregate component made of silent furnace slag, and 30% of the expandable material component made of quicklime. Then, the lateral displacement of the steel sheet pile was measured using an inclinometer.

The results are shown in Figure 3. That is, after the casing is press-fitted (Fig. 3(a)), after the completion of casting of the cement thread powder and granular material (Fig. 3(b)), and after 13 days have passed since casting (Fig. 3(c)). It can be seen that at any of the three points in time, the steel sheet pile is displaced to the opposite side of the pile due to the expansion pressure of the pile, and the surrounding ground is tightly packed to prevent loosening.

As described above, the present invention can provide an earth retaining method that can more reliably prevent deformation due to sliding failure or loosening of the surrounding ground during excavation work etc. compared to conventional methods.

[Brief explanation of the drawing]

1st [YI (a), (b), (c), (d), (e) shows the construction order of the 15th year of this book.
FIG. 2 shows an embodiment of the present invention. The four-eye diagram of the degree and displacement position, Figure 3 (a), (b), and (c) is the rlf of the present invention.
J. It is a Sekiguchi of the depth and the second place quantity which shows the example of. l... Casing 3... Cement-based powder material 6... Pile 7... Earth retaining water stop wall agent Patent attorney Hiroshi Akazawa Figure 1 (Q) (b) (C) (d) (e) Fig. 2, 51i ■(... Fig. 3 (a) (b) +wq44f! (mm) tp+death+*l (mm) (C) Stopping length (mm)

Claims (1)

[Claims] A cylindrical casing is press-fitted to a predetermined depth, a cement-based granular material having water absorption, expandability, and hydraulic properties is filled into the casing, and the cement granular material is discharged downward while the casing is closed. According to the procedure of pulling out the cement-based granular material to form a pile, the required number of piles are closely spaced and formed sequentially in a certain direction,
An earth retaining method characterized in that the group of piles constitutes an earth retaining water cutoff wall.