JPH0692709A - Grout material for fixing underwater structure and installation method therefor - Google Patents

Abstract

PURPOSE:To provide the grout material which can be forcibly fed, has good packability and cures perfectly after packing by using coarse aggregate and fine aggregate of specific sizes with cement compounded with a non-separating agent and a high-performance water-reducing agent, thereby preparing an aq. slurry having a specific compsn. CONSTITUTION:This grout material for underwater structures consists of, by weight, 300 parts cement, 200 to 260 parts water, 650 to 900 parts fine aggregate, 750 to 1100 parts coarse aggregate of <=15mm max. size, 1 to 2 parts non- separating agent, 3 to 12 parts high-performance water-reducing agent and 0.5 to 1 part AE water-reducing agent. The grout material is kneaded at about 65 to 80% water/cement ratio and the rate of the fine aggregate in the aggregate is preferably about 45 to 50% and the slump flow is >=60cm in terms of force feedability. The grout material is kneaded and is directly fed to the section to be packed in water by a piping from a mixer ship or is sent near to the section to be packed by a riser from the mixer ship. The material is forcibly fed to the desired packing section by means of a pump provided in the section.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grout material for closing and filling an underwater closed space which can be used for foundation work of an underwater submersible box and a filling method using the grout material.

[0002]

2. Description of the Related Art In the case where a structure having a predetermined shape, such as a submerged box, is prepared in advance such as an undersea tunnel, and a predetermined number of the submerged boxes are laid in water and connected to each other to form a desired tunnel structure. As a matter of course, it is necessary that each submerged box is installed and fixed at a predetermined position. However, since the seabed is not flat and there is also water flow, the bottom of the submerged box is fitted to the seabed by installing an appropriate material between the bottom of the box and the seabed surface when installing the submerged box. In addition, it is necessary to prevent water from passing under the box.

A submerged box usually has a tunnel floor formed slightly above the lower end of the box, and a space below the floor is a closed space when the submerged box is installed on the sea floor. , Rubble stones are laid as a foundation on the bottom of this floor. In the case of foundations with permeable voids like rubble,
It is necessary to properly close the gap between the rubble. This filling and blocking under the floor is performed by injecting the filling material through a small hole with a diameter of 70 to 80 mm provided on the floor surface.

Conventionally, as the filler for this kind of purpose, use of bentonite mortar or underwater non-separable concrete and non-separable mortar containing 2.0 kg / m ³ or more of the non-separating agent has been considered. However, the former bentonite mortar has a problem that its application is limited to seawater, and it is difficult to completely fill it because it permeates into the basic voids after grouting and slightly breathes. In addition, the latter underwater non-separable concrete has a problem that it is difficult to pump it with a pump etc. due to its strong viscosity, and it is not possible to cope with it especially when the injection hole is small, and there is a risk that the filling between the foundation rubble will be insufficient There is. In addition, the non-separable mortar in water has a large permeation into the basic void like the bentonite mortar.

[0005]

DISCLOSURE OF THE INVENTION For example, an underwater closed space formed between a submerged box and a rubble of a foundation when a caisson is installed,
When filling by long-distance pumping from a concrete plant ship using an injection hole provided in a submerged box or caisson bottom slab, the required projects are: 1) An underwater closed space (50 cm thick) between the foundation rubble and the bottom slab. Degree), it has fluidity that spreads to every corner, 2) non-breathing, that is, the integrity of the bottom slab is not impaired by sedimentation breathing after filling, 3) permeation into the rubble voids after filling There is negligible material subsidence, 4) it has good long-distance pumping capability without blocking even when the injection hole is as small as about 80 mm in diameter, and 5) the filled material has a stable cured body quality. Can be mentioned. The present invention is
It is intended to provide a grout material which has good fluidity, can be easily pumped by a pump or the like, has a good filling property in voids, is completely cured after filling, and is not reduced by breathing or the like.

[0006]

The present inventor has found that the non-separating agent,
It was found that a grout material made into a suitable aqueous slurry by using coarse aggregate and fine aggregate of an appropriate size for cement as a hydraulic component mixed with a superplasticizer can solve the above problems. And completed the present invention. The grout material for fixing an underwater structure of the present invention comprises 300 parts of cement and 200 to 240 parts of water.
Part, fine aggregate 650-900 parts, coarse aggregate with a maximum size of 15 mm or less 7
It is characterized by comprising 50 to 1000 parts, 1 to 2 parts of a non-separating agent, 3 to 12 parts of a high performance water reducing agent, and 0.5 to 1 part of an AE water reducing agent. Parts here refer to parts by weight, more specifically parts are replaced in units of Kg / m ³ . In addition to the above components, the grout material of the present invention may optionally contain admixtures such as stabilizers and non-separating agents which are generally used in this type of field.

As the cement as the water-curable component in the present invention, those used in this kind of field can be used, and more specifically, blast furnace slag powder, fly ash, silica powder and minerals are used for Portland cement. It is preferable to mix one or more selected from the group consisting of powders. More specifically, blast furnace cement type B or the like can be used. Water can be used as long as it is tap water such as tap water that does not contain a component that inhibits hardening of cement. The water / cement ratio is about 65-80%.

As the fine aggregate and the coarse aggregate used in the present invention, JIS standard products can be used. Of these, coarse aggregate is
From the viewpoint of pumpability and injectability, the maximum aggregate size of 15 mm or less is used. The fine aggregate ratio in the aggregate is preferably about 45 to 50% from the viewpoint of pumpability. When the fine aggregate ratio is large, the pumpability is good, but the amount of permeation into the rubble foundation is large, so the above range was set. As the non-separating agent, a cellulosic water-soluble polymer used in this type of field can be used, and a 1% aqueous solution having a viscosity of 5,000 cp or more is particularly preferable.
As the superplasticizer, those based on melamine sulfonate, which are also used in this type of field, are used. Further, a lignin sulfonic acid compound and a polyol complex are used as the AE water reducing agent.

The grout material of the present invention can be prepared according to a conventional method. For example, after coarse kneading aggregate, fine aggregate, cement and non-separating agent are kneaded, water and AE water reducing agent and then fluidizing are added. It can be performed by adding an agent (high-performance water reducing agent) and the like and kneading. The obtained grout material is 60 cm
As described above, it preferably has a slump flow characteristic of 60 to 70 cm. At the time of use, a method of directly sending by piping from a mixer ship or a method of sending from a mixer ship to a caisson box by a falling pipe and pumping with a pump provided at the bottom of the box may be used.

[0010]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

Examples 1 to 3 Blast furnace cement type B was used as cement, and after the coarse aggregate, fine aggregate, cement and non-separating agent were kneaded using a forced bread mixer (maximum kneading capacity 100 L) , Water and an AE water reducing agent, and then a high performance water reducing agent were added and kneaded to knead a grout material having the following composition. The temperature of the cement (grout material) after kneading was 20 ° ± 3 ° C., and each grout material was prepared so that the slump flow (fluidity) was a target value of 60 cm or more. The amount of air, the slump flow, the breathing rate, and the permeability to the crushed stone of the obtained grout were measured. The results are shown in Table 1. In addition,
Materials used are coarse aggregate: JIS standard product with maximum aggregate size of 15 mm or less (crushed stone: surface dry specific gravity of about 2.7) Fine aggregate: JIS standard product (sea sand: surface dry specific gravity of about 2.54) Non-separating agent, AE water reduction As the agent and the high-performance water reducing agent, the above-mentioned commercially available agents were used. The slump flow and the amount of air were tested in accordance with the Japan Society of Civil Engineers Standard “Slump flow test method for concrete (draft)” and JIS A 1128 (test method by pressure of air amount of concrete that has not yet solidified). The breathing test was conducted according to JIS A 1123 (concrete breathing test method). Permeability test into the foundation, that is, the amount of penetration into the crushed stone (amount of bite)
The test was performed with an inner diameter of 25c in a water tank filled with crushed stones with a thickness of 30 cm.
A steel cylinder with a height of 50 cm and a height of 50 cm was erected, and the grout material was filled into the cylinder to measure the bite amount by its own weight. Mortar was used as Comparative Example 1, and bentonite mortar was used as Comparative Example 2.

[0012]

[Table 1] Note) The unit of each composition in the table is kg / m ³ . *) P funnel flow time

In the case of the present invention, since the main purpose is not the purpose of producing a structure but the filling property, high strength is not required, but it is an optimum example, which is an optimum example. The strength was 50.6 kgf / cm ² .

Examples 4 to 6 The pumpability of the grout materials with various amounts of the non-separating agent was tested. In the pressure-feeding test, the mixer vessel was directly hit by a pressure-feeding pipe continuously piped from the mixer vessel to the filling site. The piping is as follows. Falling pipe 30m + Horizontal pipe 100m + Curved pipe 3 places + Flexible pipe 1 place In addition, the pipe diameter is 150mm, and the caisson bottom plate injection hole is 80mm in diameter.
Therefore, the diameter of the discharge port was set to 75 mm, and it was narrowed down toward the discharge port with a taper of 25 mm / m. The results are shown in Table 2.

[0015]

[Table 2] Note) In the table, ○ indicates good, Δ indicates poor (pressure feeding is possible but injection is insufficient), and X indicates not (not enough pressure feeding). Also. The numerical values of Example 5 of the pumping property are actually measured values.

Example 7 In the composition of Example 2 above, the maximum particle size of coarse aggregate was 20 m
When the grout material was kneaded into a m, 25 mm, or 30 mm one and the pump pressure-feeding property was measured, the pressure-feeding property was not possible in all cases. Since the discharge port was 75 mm in diameter, the injectability decreased as the diameter of the aggregate increased.

[0017]

EFFECTS OF THE INVENTION The present invention uses a coarse aggregate having a maximum size of 15 mm or less and a water-cement ratio, a fine aggregate ratio, and other admixtures as appropriate, so that the mixture can be directly fed from a mixer ship by piping. It becomes possible to carry out pressure feeding, and a grout material having good filling properties and required strength after curing can be obtained.

Claims (3)

[Claims] 1. Cement 300 parts, water 200 to 260 parts, fine aggregate 650 to 900 parts, coarse aggregate 750 to 1100 with a maximum size of 15 mm or less.
Parts, 1 to 2 parts of non-separating agent, 3 to 12 parts of high performance water reducing agent and AE
A grout material for fixing an underwater structure, which comprises 0.5 to 1 part of a water reducing agent. 2. The grout material according to claim 1, wherein the water / cement ratio is 65 to 90%, the fine aggregate ratio in the aggregate is 45 to 50%, and the slump flow is 60 cm or more. 3. The grout material according to claim 1 is kneaded and directly sent to a portion to be filled with water by a pipe from a mixer ship, or a portion from the mixer vessel to a portion to be filled with water by a falling pipe. A method for fixing an underwater structure, which comprises pumping to a target filling site with a pump provided at the site.