JP2772637B2 - Injection pipe device and ground injection method using this device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an injection pipe device capable of simultaneously injecting a plurality of injection stages and simultaneously solidifying the ground by performing desired injection in each injection stage. The invention also relates to a ground injection method using this device. (Prior art) Generally, the ground is formed by alternate layers of different grain size and water permeability, so when inserting an injection pipe into the ground and consolidating the ground through the injection liquid from this injection pipe, The injection liquid deviates into a layer having large water permeability, and the whole cannot be consolidated uniformly. Therefore, FIG. 2 (a) shows a means for solving this problem.
The construction method shown in Toshi (d) has been developed. More specifically, first, as shown in FIG. 2 (a), the ground 1 is bored, and the casing 2 is inserted therein. Next, as shown in FIG.
Insert the outer tube 3 into the inside. A plurality of discharge ports 5, 5,... 5 are opened at predetermined positions on the tube wall 4 of the outer pipe 3 at different positions in the axial direction, and these discharge ports 5, 5,. Covered with. Further, after injecting the sleeve grout 7 into the casing 2, the casing 2 is pulled out as shown in FIG. 2 (c). Thereby, the outer tube 3 is sealed with the sleeve grout 7. Next, as shown in FIG. 2 (d), strainers 8, 8,... 8 are drilled at the tip, and the inner tube 10 on which the packers 9, 9 are arranged is inserted into the outer tube 3, When the injection liquid is injected through the conduit of the inner pipe 10, the injection liquid passes through the strainer 8 and the space 11 formed between the upper and lower packers 9, 9 as shown by arrows, and from the discharge port of the outer pipe 3 to the rubber sleeve 6.
To spread and infiltrate the ground 1 around the stage by breaking the sleeve grout 7. [Problems to be Solved by the Invention] In the method shown in FIG. 2 described above, the injection liquid does not deviate vertically along the outer tube 3 due to the presence of the sleeve grout 7, and it is ensured at every predetermined injection depth. Penetrates and solidifies. However, in this method, the inner tube 10 is pulled up for each injection stage (the length of one injection stage is usually 25 to 50 cm).
The operation is complicated because the strainer 8 of 10 and the discharge port 5 of the outer tube 3 correspond to each other and the injection liquid is repeatedly injected from each discharge port 5, so that the operation is complicated. Since a large amount of the injection liquid is discharged, the permeation resistance pressure (injection pressure) of the ground increases, and uniform injection becomes impossible. For this reason, the injection rate must be reduced at a low pressure by reducing the injection rate per minute and increasing or increasing the strainer as much as possible so as not to cause intra-tube resistance. In addition, in the above-described method, when the space between the upper and lower packers 9 and 9 is widened and a large number of stages are simultaneously injected, the injection liquid concentrates only on the discharge port located in the ground layer having the lowest injection resistance. Uniform injection is not possible. Therefore, an object of the present invention is to provide an injection device that simultaneously injects a plurality of injection stages and simultaneously performs a desired injection in each injection stage, thereby consolidating the ground very quickly, and a ground injection method using the device. Is to do. [Means for Solving the Problems] In order to achieve the above object, according to the present invention, an outer pipe installed in the ground and having a plurality of discharge ports opened at different positions in the axial direction, An inner pipe, which is loosely inserted in the outer pipe and has a plurality of injection ports opened at different positions in the axial direction, and spaced apart at different positions in a longitudinal direction of a pipe formed in a gap between the inner pipe and the outer pipe. And three or more packers arranged, a plurality of mutually independent spaces are formed between the adjacent packers, and each of these spaces has at least one outer pipe discharge port and a common space. The inner pipe passage communicating with the inner pipe passage is characterized by being located.Furthermore, according to the method of the present invention, the gap between the outer pipe and the ground is sealed with a sleeve grout using the injection pipe device, and then the inner pipe is formed. The infusate is introduced from the pipe line, and the infusate is It is characterized in that it is injected into each space from a pipe outlet, and simultaneously injected into the ground via an outer pipe outlet located in each space. Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a sectional view of an apparatus according to the present invention. In FIG. 1, the injection pipe 20 has an outer pipe 21 and an inner pipe 22. When the injection pipe 20 is installed in the ground 23, the outer pipe 21 is first installed in the ground 23.
This installation is performed by a method similar to that shown in FIGS. 2 (a) and 2 (b). The outer pipe 21 has pipe walls at different positions in the axial direction.
Arbitrary plural discharge ports 25, 25... 25 are opened in 24.
Each of the discharge ports 25 is covered with a rubber sleeve 26. Next, the inner tube 22 is loosely inserted into the outer tube 21. The inner pipe 21 also has a plurality of arbitrary injection ports 28 on the pipe wall 27 at different positions in the axial direction,
28..28 are opened. The injection ports 28, 28, and 28 are as small as possible and are squeezed and opened, thereby generating a pressure in the inner pipe 22 with respect to the flow rate of the injection liquid per minute, and the injection liquid from the injection port 28. The fuel is injected into the space 31 described later. Further, at least three packers 3 are provided at different positions in the longitudinal direction of the conduit 29 formed in the gap between the inner tube 22 and the outer tube 21.
30 are arranged at an interval, so that an adjacent space 31 is provided between these adjacent packers 30, 30, that is, between adjacent upper and lower packers 30, 30.
Are formed in the longitudinal direction. Moreover, each of these spaces
The packers 30, 30 are arranged on the 31 such that at least one outer tube outlet 25 and at least one inner tube outlet 28 are located. At the time of injection, first, a sleeve grout 32 is injected into the gap between the outer tube 21 and the ground 23 to seal it using the injection pipe device 20 configured as described above. This sleeve grout 32
Is performed in the same manner as in FIG. 2 (c). Next, the injection liquid is introduced from the pipe 22a of the inner pipe 22, and the injection liquid is injected into the respective spaces 31, 31 from the injection ports 28, 28,. The rubber sleeve 26 is pushed and expanded through the discharge port 25 of the outer tube 21 located at the position 31, 31..., And the sleeve grout 32 is cracked and injected into the ground 23. [Operation] In the present invention, since a plurality of independent spaces are provided at positions corresponding to the respective injection stages, even if the ground 23 near the plurality of discharge ports 25 has different water permeability, the sleeve grout 32 Even if the injection resistance differs due to the consolidated state or the different consolidated width, or even if the injection resistance changes during injection, the desired discharge amount can be obtained from each discharge port 25, and the ground can be reliably secured. To consolidate. Moreover, since the injection liquid is injected into the space even when injected at a considerably high pressure, the injection ground is not scoured by the injection,
The soil particle structure is homogeneously injected into the ground without being destroyed. FIG. 3 shows the resistance pressure (ground pressure) (kg / cm ² ) and the flow rate from the injection port 28 (nozzle) at each injection pressure from the injection port 28 (expressed as the pump pressure when the injection liquid is supplied). (L /
FIG. 4 is a graph showing the same relationship as FIG. 3 when the nozzle diameter (injection port diameter) is changed. In this case, the resistance pressure is obtained by attaching a hose to the injection port, providing a valve at the tip, adjusting the valve, measuring the pressure in the hose, and assuming the ground pressure. As apparent from FIGS. 3 and 4, for example, when the pump pressure is 80 kg / cm ² , even if the resistance pressure (kg / cm ² ) in the ground changes, the resistance pressure is about 50 kg / cm ^2. Until the flow rate from the nozzle is constant. Therefore, in the present invention, if the pump pressure is increased to about 1.2 to 1.3 times or more higher than the resistance pressure, a predetermined discharge amount can be obtained regardless of the change in the resistance pressure, even if the ground permeability is different. In addition, the ground can be securely consolidated at each discharge port. In other words, the ground has different water permeability for each of the upper and lower layers, and accordingly, the injection resistance is different, and the penetration resistance from the cracks in the sleeve grout is also different, but nevertheless, the desired flow rate is always ensured, Furthermore, the ground pressure (resistance pressure) changes due to various causes, but nevertheless, a predetermined flow rate is always ensured. Therefore, according to the present invention, a plurality of grounds at different axial positions are provided. A desired discharge flow rate is simultaneously secured from the discharge ports, and the grounds of the plurality of injection stages are simultaneously and reliably consolidated. [Effects of the Invention] As described above, according to the present invention, simultaneous injection can be performed in a plurality of injection stages, and a predetermined discharge amount is maintained from each discharge port regardless of difference or variation in injection resistance. This allows the ground to be securely and easily consolidated.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a cross-sectional view of a specific example of the apparatus of the present invention, and FIGS. 2 (a) to 2 (d) are cross-sectional views of a known injection step. FIG. 4 is a graph showing the relationship between the resistance pressure and the flow rate from the nozzle. 20 ... Injection pipe, 21 ... Outer pipe, 22 ... Inner pipe, 22a ... Inner pipe line, 23 ... Soil, 25 ... Discharge port, 28 ... Injection port, 30 ...
... packer, 31 ... space, 32 ... sleeve grout.

Claims (1)

(57) [Claims] An outer pipe installed in the ground and having a plurality of discharge ports opened at different positions in the axial direction, and an inner pipe loosely inserted into the outer pipe and having a plurality of injection ports opened at different positions in the axial direction. Three or more packers arranged at intervals at different positions in the longitudinal direction of a conduit formed in the gap between the inner pipe and the outer pipe, and an independent space is provided between the adjacent packers. An injection pipe device in which a plurality of pipes are formed, and at least one outer pipe outlet and an inner pipe outlet communicating with a common inner pipe are located in each of these spaces. 2. An outer pipe installed in the ground and having a plurality of discharge ports opened at different positions in the axial direction, and an inner pipe loosely inserted into the outer pipe and having a plurality of injection ports opened at different positions in the axial direction, Three or more packers arranged at different positions in the longitudinal direction of a pipe formed in the gap between the inner pipe and the outer pipe, and three or more packers are provided at intervals, and a space independent of each other is provided between the adjacent packers. Are formed in each of these spaces, and at least one outer pipe outlet and an inner pipe outlet communicating with a common inner pipe are used in each of these spaces. After the gap between the ground and the ground is sealed with a sleeve grout, an injection liquid is introduced from the inner pipe line, the injection liquid is injected from the inner pipe injection port into each space, and the outer pipe discharge port located in each space. Ground injection method characterized by simultaneously injecting into the ground through