JPH028410A - Method of elevation construction of ground - Google Patents

Abstract

PURPOSE:To elevate the whole ground by the freezing expansion pressure of a peripheral ground by horizontally burying a freezing pipe into an underground ground extending between relatively excavated ditches, supplying the inside of the pipe with a coolant and freezing the peripheral ground. CONSTITUTION:A ground level is partitioned in a fixed area, ditch holes 1 are excavated along the relative two sides of the partition, and a freezing outer pipe 7, a nose section of which is closed, is buried between the ditch holes 1 by using a boring machine, a press-fitting device, etc. A freezing inner pipe 8, a nose section of which is opened, is inserted into the freezing outer pipe 7, a coolant such as a sodium chloride aqueous solution is circulated in the inner and outer pipes 7, 8, and frozen soil (a) is created concentrically centering around the freezing pipes. Mortar, etc. are injected to a section not frozen between adjacent frozen soil (a) and the section not frozen is reinforced, hot water is circulated into the inner and outer pipes 7, 8, mortar is injected to a melting section immediately after frozen soil is melted, thus reinforcing the ground.

Description

[Detailed description of the invention] (Industrial application field) The present invention relates to a ground uplift method.

(Prior Art) Conventionally, there was no other suitable method for raising the level of low-lying wetlands other than embanking the ground.

(Problems to be Solved by the Invention) However, the conventional embankment construction method has the following problems.

(1) Thick deposits of low wetlands and alluvial layers will cause consolidation settlement and swell due to embankment, which will require a great deal of cost and time to carry out ground improvement work as a countermeasure.

(2) In densely populated areas, compensation costs associated with relocation, etc. will be enormous.

The present invention has been proposed in view of the problems of the above-mentioned prior art, and its purpose is to prevent consolidation settlement and slab bulges from occurring, and which do not interfere with the daily lives of residents at all. The purpose of this technology is to provide a method of raising the ground by gradually lifting the ground without causing any damage.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the ground uplift method according to the present invention divides the ground surface into a certain area, and divides the ground surface into a certain area along two opposing sides on the outside. Then, a frozen pipe is buried horizontally between the two excavated trenches in the underground ground of the section, and then a coolant is supplied into the frozen pipe, and the ground around the frozen pipe is buried. It is characterized by freezing the ground and causing the entire ground to rise due to the freezing expansion pressure.

(Function) According to the present invention, the ground surface is divided into a certain area in this way, and the ground is drilled into the underground ground between the trenches excavated along the two outer facing sides of the divided area. Since frozen pipes are buried horizontally and coolant is supplied into the frozen pipes, the surrounding ground is gradually cooled through heat exchange between the frozen pipes and the surrounding ground, and eventually frozen soil is created. The freezing expansion pressure that occurs during this process causes the entire ground above it to rise.

(Example) The present invention will be described below with reference to the illustrated embodiments.

The ground surface (A) is divided into fixed areas, and groove holes (1) are excavated along two opposing sides on the outside of the divided sections.

(2) and (3) are the inner and outer retaining walls installed in each groove (1), (4) is the raised wall, and (5) is the strut.

The inner earth retaining wall should be raised higher than the ground level (A) by the height equivalent to the raised height h, and the outer wall surface in contact with the ground should be coated with grease or the like to prevent it from being lifted up along with the ground when the ground rises. Alternatively, attach a vinyl sheet (6), etc.

Next, a polling machine or a press-fitting device is installed in one of the excavated trenches (1), and the frozen outer pipe whose tip is closed between the opposing trenches (]) (1) in the ground. (7) will be buried.

Next, the inner cryo tube (8) with an open tip is inserted concentrically into the outer cryo tube (7), and between the freezing device (B) on the ground and the inner and outer tubes (8) (7). Connect brine pipes (9) and (10) to the pipes, and provide return and return pipes so that the coolant can circulate between the above-ground freezing device (B) and both the inner and outer pipes (7) and (8).

Incidentally, a flexible joint (11) is provided in the middle of the brine pipes (9) and (10) so as to be able to absorb displacement caused by upheaval of the ground.

Next, the freezing device (B) is operated, and when a low-temperature liquid, such as a cooled sodium chloride aqueous solution, is supplied as a coolant to the freezing inner tube (8) using a pump, the low-temperature liquid flows from the tip of the freezing inner tube (8) into the inner tube. It passes between the pipe (8) and the frozen outer pipe (7), and is further sent to the freezing device (B) through the return brine pipe (10), where it is cooled again and frozen again. (8), and the cryogenic liquid is thus continuously circulated between the cryotube and the freezing device (B).

Eventually, the low-temperature liquid and the surrounding ground exchange heat through the freezing outer tube (7), and freeze concentrically around the freezing tube (a).
is created (see Figure 5) and continues to grow.

During the creation process of this frozen ± (a), the upper ground (b) gradually rises due to the freezing expansion pressure generated by the volume increase when soil water freezes, and as the frozen ± (a) grows. The amount of prominence increases.

At this time, mortar or the like is injected into the unfrozen parts between adjacent frozen parts (a) and (a) to reinforce them.

After the ground has risen by the planned amount, the operation of the freezing device is stopped, and after the reinforcing strength by the mortar etc. has been developed, warm water is circulated using the inner and outer pipes (7) and (8) to forcibly Thaw frozen soil. Immediately after melting, mortar is injected into the melted area to strengthen the ground that has become soft due to melting and prevent subsidence.

Furthermore, as mentioned above, the reason why frozen soil is not continuous in the horizontal direction is
When frozen soil thaws, it becomes soft and prone to subsidence, so instead of freezing the entire ground horizontally, we create unfrozen sections between the frozen soil and strengthen the spaces by injecting mortar. This is to prevent ground subsidence.

Note that the number of stages of the freezing tubes is determined by the raised height h of the ground.

(Effects of the Invention) According to the present invention, as described above, the ground surface is divided into a certain area, and the trenches excavated along the two outer facing sides of the divided area are used to extend into the underground ground. Coolant is continuously supplied into freezing pipes buried horizontally, and the freezing expansion pressure generated by freezing the ground around the pipes gradually raises the entire divided ground evenly, As a result, the ground can be raised without consolidating the soft ground that exists in the upper strata of low-lying wetlands, and the entire divided ground is evenly and gradually raised, making it easier for residents to The ground can be raised without any hindrance to people's daily lives.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view showing an embodiment of the ground freezing device applied to the ground uplift method according to the present invention, Fig. 2 is a plan view thereof, and Fig. 3 is a longitudinal sectional view showing details of the freezing pipe. , FIG. 4 is a vertical cross-sectional view showing the state of implementation of the construction method of the present invention, and FIG. 5 is a vertical cross-sectional view showing the process of creating frozen soil in the ground by the method of the present invention. (1)-・Slot hole, (7)-・Freezing outer tube, (8
)--Freezing inner pipe, (9) (10)-Brine piping, (^)--Ground surface, (B)--Freezing device. Agent: Patent attorney: Shige Okamoto, 2 other people

Claims (1)

[Claims] The ground surface is divided into a certain area, trenches are excavated along the two outer opposing sides of the division, and then a frozen pipe is inserted between the two excavated trenches into the underground ground of the division. A ground uplift method characterized by burying the frozen pipe horizontally, then supplying a coolant into the frozen pipe, freezing the ground around the frozen pipe, and raising the entire ground by the freezing expansion pressure at that time.