JPH09170904A - Measure weight - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a measure weight performing precise top end position measurement without causing variation in a measurement value due to specific gravity and viscosity of soil cement, etc., during placing, in constructing subsurface structure. SOLUTION: A measure weight 3 comprises a hollow body of specified volume in which optional pieces of steel balls are charged, and a supporting member which suspends the hollow body, and, the measure weight is so constituted that weight per unit volume is varied according to the number of charge steel balls. The hollow body comprises a sphere 4, and the supporting member comprises a cylindrical socket 6 fix-attached to an opening part 4a, a plug 7 screwed in the socket 6, and an eye bolt 9 provided with a screw part 9b screwed in a tapping hole 7c of the plug 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention accurately determines the top end of ready-mixed concrete or soil cement when constructing an underground structure such as cast-in-place pile or underground wall in foundation work of buildings and structures. More particularly, the present invention relates to a measuring weight that can freely change the weight per unit volume according to the hardness and softness of fresh concrete or soil cement to be placed, the specific gravity and the viscosity.

[0002]

2. Description of the Related Art In recent years, a shortage of industrial waste treatment facilities has become serious, and various techniques have been proposed to effectively use the excavated soil by coping with the problem of shortage of excavated soil as a residual soil during construction work. Being developed. One of them is the use of mud mortar, that is, a method of adding cement and water to excavated soil and kneading it to use it for a solid support board, foundation piles, earth retaining walls, etc. This mud mortar is also called soil cement, and it is also satisfactory in terms of strength and durability by adding a few percent of cement to excavated soil or its supplementary material and compacting it near the optimum water content ratio. The characteristics to be obtained are obtained.

As a foundation work, a cast-in-place pile is first constructed by excavating an underground hole to a depth of several tens to several hundreds of meters by a construction method such as a benot construction method, an earth drill construction method and a reverse construction method. At the time of excavation of this underground hole, the excavation work is performed by filling the excavation hole with mud water as a stabilizing liquid in order to stabilize the hole wall. After the excavation is completed, a reinforced cage is installed in the underground hole, a tremie pipe is then installed, and fresh concrete and soil cement are placed to replace mud water.

There are methods such as a bottom lid type, a plunger type, and a ball packing type in the tremie method, but the plunger type is generally widely used. This is a construction method in which a plunger is installed after the tremie pipe is installed and the plunger is hung with a wire. Since the quality of ready-mixed concrete or soil cement pouring by the tremy method may deteriorate due to the inclusion of foreign matter such as slime or laitance, it is necessary to keep the execution accuracy sufficiently high.

[0005] At the time of execution, ordinary ready-mixed concrete, ready-mixed concrete with improved fluidity, or a certain amount of cement milk obtained by separately agitating cement and water in a cement silo is sent to a mixer together with the excavated soil to a sufficient degree. After kneading to produce soil cement, when pouring, raw concrete or soil cement is placed up to a height of about 5 m from the tip of the tremie pipe, and then the tremie pipe is pulled up by about 3 m, and then about 3 to 5 m of raw concrete or soil cement is re-applied. By repeating the operation of pulling up the tremie pipe after placing it, the tip of the tremie pipe is always positioned about 2 m below the top of the fresh concrete or soil cement, and the cement milk is blown up sequentially while preventing it from blowing up. It is necessary to carry out the installation work.

In the above-mentioned construction method, it is particularly required to accurately measure the top end position of the fresh concrete or soil cement during the pouring and the top end position at the final pouring. Therefore, conventionally, as shown in FIG.
A method is used in which the lower end of the measuring weight 1 is applied to the top end of ready-mixed concrete or soil cement to measure the top end position from the drop length of the wire 2. There is also a method of measuring the top end of green concrete by sensing the boundary surface with slime by using an interface meter in which a cord with a measure with a sensor suspended is wound around a drum.

[0007]

However, when such an iron measuring weight is used, the measured value tends to vary due to the penetration of the measuring weight due to the specific gravity or viscosity of green concrete or soil cement, and the accuracy is There is a problem that it is not possible to perform accurate top end position measurement.

For example, ordinary ready-mixed concrete contains aggregates such as crushed stone, and since the slump is about 15 to 20 cm, even an iron weight having a weight per unit volume of 7.8 has a small amount of penetration into the ready-mixed concrete. , Measurement error is 30-50c
Although it is within the permissible range of about m, as mentioned above, soil cement, unlike fresh concrete, does not contain aggregate, has low viscosity and specific gravity as small as 1.5. However, the measuring weight penetrates into the soil cement 3 to 5 meters from the top, and the error becomes large, and accurate measurement cannot be performed.

The above slump refers to concrete that has not solidified yet. Normally, in the slump test, the iron cone is filled with concrete to be measured, and when the cone is pulled up vertically, the fall of the concrete top is measured by cm.
It is called "Slump cm".

Further, since recent concrete for underground walls is required to have high strength, a concrete having an increased fluidity by increasing the amount of cement is used. Therefore, when soil cement is used. In some cases, the measuring weight penetrates into the ready-mixed concrete as in the above. In response to the above, there is also a means to use as a measuring weight the one in which the casting material is put into an arbitrary steel pipe and hardened, but since the specific gravity cannot be finely adjusted, it is not possible In some cases, the measuring weight may float due to the gel in the contact area, and the satisfactory result has not been obtained.

Therefore, in view of the above, the present invention provides a measuring weight capable of performing accurate top end position measurement without variation in measured values due to specific gravity or viscosity of green concrete or soil cement. It is intended.

[0012]

In order to achieve the above object, the present invention provides a measuring scale for measuring the top end position by hitting the top end of ready-mixed concrete or soil cement in the middle of pouring. In the weight, the above-mentioned measuring weight is composed of a measuring weight whose weight per unit volume can be changed, a hollow body having a predetermined volume, and a supporting member suspending the hollow body with a cord, and the filler is put into the hollow body. A scale weight for changing the weight per unit volume by the above, the scale weight, a hollow body having a predetermined volume into which an arbitrary number of steel balls are charged, and a support member for suspending the hollow body with a cord. According to another aspect of the present invention, there is provided a measuring weight, wherein the weight per unit volume is changed according to the number of steel balls charged.

An appropriate amount of fluid or solid is used as the filling material, water is used as the fluid, the hollow body is a sphere, and the supporting member is a cylindrical socket fixed to the opening of the hollow body. And an eyebolt having a screw shaft that is screwed into a threaded hole of the plug.

According to such a measuring weight, at the time of use, a fluid or solid filling or an arbitrary number of steel balls is introduced through the socket fixed to the opening of the hollow body, and the plug is screwed and fixed to this socket. Then insert the eyebolt's screw shaft, connect the cord to this eyebolt, and hang it down into the underground hole at the site where the underground structure is to be built.The bottom surface of the measuring weight is the top end of fresh concrete or soil cement. And measure the top end position from the descent length of the cord. At this time, the weight per unit volume can be changed depending on the number of fluids or solid fillings and steel balls charged in the hollow body, so the number of steel balls charged can be changed according to the specific gravity or viscosity of fresh concrete or soil cement. By changing the amount, the penetration amount of the measuring weight becomes extremely small, and the effect that the measurement error is kept within the allowable range is obtained.

Therefore, this measuring weight is made of soil cement whose specific gravity is smaller than that when using normal ready-mixed concrete,
It is especially useful for measuring the crown position in the construction method using ready-mixed concrete in which the amount of cement is increased to improve the fluidity.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a measuring weight according to the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of an essential part showing a measuring weight 3 to which the present embodiment is applied. In the figure, 4 is a hollow spherical body as a hollow body having a predetermined volume. A predetermined number of steel balls 5,
5 has been thrown in. Therefore, the weight per unit volume of the spherical body 4 can be changed by selecting the number of steel balls 5 and 5 to be charged. The hollow spherical body 4 can be easily manufactured by welding and fixing two bowl-shaped bodies prepared in advance by the welding portion 10. In addition, sphere 4
The shape is not limited to the shape shown in the figure, and may be another shape such as a square shape as long as it is a hollow body.

Not only the steel balls 5 and 5 but also other filling materials may be put into the sphere 4 in order to change the weight per unit volume of the sphere 4. The filling material is not particularly limited, and water or other suitable amount of fluid, or appropriate steel material, stone, or any other solid material at the work site can be used. The point is that by filling the spherical body 4, the weight of the measuring weight 3 can be set to an optimum weight per unit volume according to the ready-mixed concrete or soil cement to be placed.

Next, a support member for suspending the hollow sphere 4 with a cord will be described. That is, 6 is a cylindrical socket fixed to the opening 4a of the spherical body 4 by welding or the like, and the plug 7 is screwed and fixed to this socket 6 with the O-ring 8 interposed. As shown in FIG. 2, the plug 7 is composed of a body 7a and a head portion 7b, and a threaded hole 7c is screwed from the surface portion of the head portion 7b to the inside of the body 7a. 9 is an eyebolt, and this eyebolt 9
A screw shaft 9b provided on the base portion 9a of the above is screwed into the threaded hole 7c of the plug 7.

The materials of the sphere 4, the socket 6, the plug 7 and the eyebolt 9 are not particularly limited and may be appropriately selected. However, stainless steel having a high rust preventive ability is used in terms of maintenance and maintenance. preferable. Alternatively, stainless steel balls may be used as the steel balls 5.

According to such a measuring weight 3, an arbitrary number of steel balls 5 and 5 are put in through the cylindrical socket 6 fixed to the opening 4a of the sphere 4 at the time of use, and then O is inserted into the socket 6. After the plug 7 is screwed and fixed with the ring 8 interposed, the screw shaft 9b provided on the base portion 9a of the eyebolt 9 is attached to the plug 7
It is screwed into the threaded hole 7c, and a measuring cord (not shown) is connected to the eyebolt 9 and suspended.

Then, a rebar cage and a tremie pipe are built in the underground hole excavated to a depth of several tens to several hundreds of meters by a known construction method for constructing an underground structure such as a cast-in-place pile or an underground continuous wall. After pouring the fresh concrete or soil cement into it by substituting it with mud water as a stabilizing liquid, the measuring weight 3 according to the present invention is lowered into the underground hole, and the lower surface of the measuring weight 3 is placed on the raw concrete or soil. It is applied to the top of the cement and the top position is measured from the length of descent of the measurement cord.

Based on the above-mentioned measured values, after pouring fresh concrete or soil cement up to a height of about 5 m from the tip of the tremie pipe, the tremie pipe is pulled up by about 3 m, and again 3 to
After pouring 5 m of fresh concrete or soil cement, the top end position is measured using the measuring weight 3, and the operation of pulling up the tremie pipe again is repeated. Then, the pouring work is continued so that the tip of the tremie pipe is located about 2 m below the top of the ready-mixed concrete or soil cement.

Although the above description has described the construction example of placing concrete for underground piles using ordinary ready-mixed concrete or soil cement, the same applies to the case of using ready-mixed concrete with improved fluidity instead of these. The measuring weight 3 according to the present embodiment can be used.

During the above-mentioned work, the weight per unit volume of the spherical body 4 depends on the number of the steel balls 5 and 5 charged in the hollow spherical body 4 of the measuring weight 3 as described above or by the filling material. Since it is possible to change, the number of steel balls 5 and 5 and the amount and type of fillers can be changed according to the specific gravity and viscosity of ready-mixed concrete and soil cement, and the measurement of the top end position will vary. Accurate measurements can be made without this occurring.

That is, when soil cement is used, the number of steel balls 5 and 5 and the amount of filler to be charged are reduced as compared with the case of using normal ready-mixed concrete. Then, since the weight of the measuring weight 3 per unit volume is reduced, the amount of the measuring weight 3 penetrating into the soil cement is extremely small, and the measurement error can be kept within the allowable range. Therefore, the scale weight 3 of the present embodiment is required to have high strength such as soil cement which does not contain aggregate and has a smaller specific gravity than normal ready-mixed concrete containing aggregate, or concrete for underground continuous wall. It is particularly effective for measuring the top position in the construction method using ready-mixed concrete with increased flowability.

In place of the means for changing the number of steel balls 5, 5 for changing the weight per unit volume of the measuring weight 3, a filling material made of a fluid or solid is measured in the spherical body 4. The same effect can be obtained by using a means for charging after that.

[0027]

As described in detail above, the measuring weight according to the present invention is used in the underground structure by putting an arbitrary number of steel balls or an appropriate amount of filler in the hollow body and suspending it with a supporting member and a cord. When descending into the underground hole at the construction site, and applying the lower surface of the measuring weight to the top of soil cement or ready-mixed concrete to measure the top position from the descent length of the cord,
Since the weight per unit volume can be changed depending on the number of steel balls and the amount of water put into the hollow body, the penetration amount of the measuring weight is extremely small regardless of the specific gravity or viscosity of fresh concrete or soil cement, and the measurement error The effect of being minimal is obtained.

In particular, soil cement, unlike fresh concrete, does not contain aggregates, has low viscosity and low specific gravity, and therefore an iron measuring weight penetrates 3 to 5 meters from the top for accurate measurement. However, the measuring weight according to the present invention can improve the accuracy of concrete pouring work by solving the above problems.

Further, the specific gravity can be finely adjusted by changing the number of steel balls to be put in the hollow body or the filling material composed of fluid or solid matter, and the specific gravity can be measured by gel at the contact portion between fresh concrete or soil cement and muddy water. A great effect is provided that a measuring weight is provided that can always perform accurate top end position measurement without the phenomenon that the weight floats.

[Brief description of the drawings]

FIG. 1 is a sectional view of an essential part showing a measuring weight to which this embodiment is applied.

FIG. 2 is a side view showing the structure of the plug used in this embodiment.

FIG. 3 is a side view showing a state when a conventional iron measuring weight is used.

[Explanation of symbols]

 3 ... Measuring weight 4 ... Sphere 5 ... Steel ball 6 ... Socket 7 ... Plug 7a ... Main body 7b ... Head 7c ... Screw cutting hole 8 ... O-ring 9 ... Eye bolt 9a ... Base 9b ... Screw shaft 10 ... Welding part

Claims (9)

[Claims] 1. A scale weight for measuring the top end position by hitting the top end of ready-mixed concrete or soil cement in the process of pouring in the underground hole, wherein the scale weight is changed in weight per unit volume. A scale weight that can be used. 2. A measuring weight for measuring the top end position by hitting the top end of ready-mixed concrete or soil cement in the process of pouring in the underground hole, wherein the measuring weight is a hollow having a predetermined volume. A measuring weight comprising a body and a supporting member suspending a hollow body with a cord, and changing a weight per unit volume by charging a filling material into the hollow body. 3. A scale weight for measuring the top end position by hitting the top end of ready-mixed concrete or soil cement in the process of pouring in the underground hole, wherein the scale weight has a predetermined volume. And a supporting member for suspending the hollow body with a cord, and the weight per unit volume is changed depending on the number of the steel balls charged. . 4. The measuring weight according to claim 2, wherein an appropriate amount of fluid is used as the filling material. 5. The measuring weight according to claim 2, wherein a solid material is used as the filling material. 6. The measuring weight according to claim 4, wherein water is used as the fluid. 7. The scale weight according to claim 2, 3, 4, 5 or 6, wherein the hollow body is a sphere. 8. The support member comprises an eyebolt having a cylindrical socket fixed to an opening of a hollow body, a plug screwed into the socket, and a screw shaft screwed into a threaded hole of the plug. Claims 2, 3, 4, 5, 6 or 7
The scale weight shown. 9. The measuring weight according to claim 8, wherein stainless steel is used as a material for the steel ball, sphere, socket, plug and eyebolt.