JP6563343B2 - Frozen soil impermeable walls - Google Patents

Description

  The present invention relates to a method for creating a frozen soil type impermeable wall.

  Conventionally, in order to stop the water in the ground, a frozen soil type impermeable wall formed by freezing the ground around the freezing pipe by circulating a coolant through a freezing pipe embedded in the ground.

  When constructing a frozen soil type impermeable wall, there was a method of measuring the temperature of the frozen soil wall with a temperature measuring tube embedded around the frozen tube and confirming that the frozen soil wall was formed to a predetermined thickness. (For example, refer to Patent Document 1). There is also a method of controlling the coolant temperature by embedding a thermometer around the freezing pipe and calculating the optimum coolant temperature using the ground temperature data and coolant temperature data measured by the thermometer. (For example, see Patent Document 2).

  When creating a frozen soil type impermeable wall, if there is a location where the groundwater flow is concentrated and the frozen soil does not close, etc., the groundwater flow rate will be reduced by the chemical injection method, freezing pipes will be additionally installed, groundwater It was common to take measures to promote freezing, such as pumping water upstream and pouring water downstream.

JP 2006-263557 A JP 2009-121174 A

  When taking the above-described freezing promotion measures, basically, boring is necessary at a place where frozen soil does not close. However, if there are obstacles in the ground, and the interval between freezing pipes in the vicinity of the obstacles is relatively wide, the formation of frozen soil is delayed and the groundwater flow is concentrated and the frozen soil does not close. Boring was not possible. In addition, if the frozen water is not closed due to concentration of freezing pipes even though the freezing pipes are arranged at regular intervals, it is difficult to predict in advance where the non-closed part will occur, so the creation of a frozen soil type impermeable wall After starting, it was necessary to investigate the position of the unclosed part.

  In addition, when a frozen soil type impermeable wall and another type of impermeable wall are combined to form an integral impermeable wall, the connection part becomes an unfrozen part and the groundwater flow is concentrated, and the two may not be integrated. There was sex. If the distance between the freezing pipe of the connection part and the other type of impermeable pipe is reduced, the possibility that an unfrozen part remains in the connection part decreases, but if the separation is too small, the freezing pipe and the other type of impermeable wall will be separated. There was a risk that the work could not be done due to contact due to construction errors.

  The present invention has been made in view of the above-mentioned problems, and the object of the present invention is to predict a place where frozen soil is difficult to close in advance, and to prevent freezing soil type shields that can quickly take measures to promote freezing. It is to provide a method for creating a water wall.

  In order to achieve the above-described object, the first invention includes a step a in which a plurality of freezing pipes are installed on a freezing pipe arrangement line in the ground, and a pre-frozen soil is provided at a place where the freezing pipe installation interval is larger than a predetermined interval. A frozen soil type impermeable wall construction method comprising: a forming step b; and a forming step c forming a frozen soil at a place where the freezing pipe is installed at a predetermined interval.

  In the first invention, when installing a plurality of freezing tubes on the freezing tube arrangement line of the ground in the step a, a location where the freezing tube installation interval is larger than a predetermined interval is provided, and the freezing tube is installed in the step b. By forming the preceding frozen soil at a location where the interval is larger than the predetermined interval, it is possible to reliably close the location where the formation of frozen soil is likely to be delayed.

In 1st invention, it is desirable to apply the auxiliary construction method for freezing promotion to the location where formation of frozen soil is overdue in the said process c.
The construction period can be shortened by applying an auxiliary construction method for promoting freezing to the place where the formation of frozen soil is delayed in step c.

In the first invention, before the step c, a plurality of temperature measuring tubes are installed in parallel with the freezing tube arrangement line, and a predetermined time curve of the temperature measured using the temperature measuring tube in the step c is set. The number of days remaining until the underground temperature reaches the target value may be estimated from the temperature decrease tendency during this period, and the location to which the auxiliary construction method for promoting freezing is applied according to the number of days remaining.
In step c, by estimating the number of days left until the underground temperature reaches the target value, it is possible to predict in advance where the frozen soil is difficult to close, and to determine where the freeze promotion measures should be taken quickly and reliably. it can.

In the first invention, a step d in which the formation of the frozen soil is intentionally generated in the step c and the subsequent frozen soil is formed in the portion in which the formation of the frozen soil is delayed after the step c. May further be provided.
If the location where the formation of frozen soil is delayed is intentionally generated in step c, the flow path of the groundwater is secured, and the frozen soil in other portions is easily formed. In addition, it is possible to predict in advance where the frozen soil is difficult to close, and to quickly take measures to promote freezing.

In the first invention, a temperature measuring tube may be added adjacent to the location where the formation of the frozen soil is delayed in step c.
If a temperature measuring tube is added adjacent to a location where the formation of frozen soil is delayed, it is easy to grasp the formation status of frozen soil.

In the first invention, when the temperature measuring tube is installed, the distance between the freezing tube arrangement line and the temperature measuring tube is smaller than the assumed freezing radius of the freezing tube or the predetermined interval in plan view. desirable.
Properly measure the temperature of the ground during the formation of frozen soil by making the distance between the freezing tube placement line and the temperature measuring tube smaller than the expected freezing radius of the freezing tube or the predetermined installation interval of the freezing tube in plan view. be able to.

  The second invention is a method for constructing a frozen soil type water-impervious wall continuously formed with another type of water-impervious wall, the first method being provided on an extension of the other type of water-impervious wall in a plan view. A plurality of freezing pipes and a second freezing pipe provided adjacent to and parallel to the water shielding wall of the other system in plan view are provided to form the frozen soil type water shielding wall. This is a frozen soil type impermeable wall construction method characterized by being smaller than the installation interval of the freezing pipes.

  In the second invention, for example, the other type of water shielding wall is a steel pipe sheet pile, and the second frozen pipe is provided in the steel pipe at the end of the steel pipe sheet pile.

  Since the material constituting the other type of impermeable wall generally has a higher thermal conductivity than the ground, the first freezing pipe provided on the extension of the impermeable wall of the other type in plan view and the other in plan view. If the interval between the second freezing pipe provided adjacent to the water barrier wall of the system in parallel is made smaller than the installation interval of the plurality of freezing pipes provided to construct the frozen soil type water barrier wall, The space between the impermeable wall of another method and the frozen soil type impermeable wall can be reliably frozen.

  ADVANTAGE OF THE INVENTION According to this invention, the construction method of the frozen earth system impermeable wall which can estimate the location where frozen soil is hard to close beforehand, and can take freezing promotion measures reliably at an early stage can be provided.

The figure which shows each process for creating the frozen soil system impermeable wall 27 The figure which shows the cross section of the perpendicular direction of the ground 2 Example of a graph showing the relationship between freezing operation days and temperature The figure which shows the flowchart of the construction method of the frozen earth system impermeable wall 27 The figure which shows the flowchart of the other construction method of the frozen earth system impermeable wall 27 Diagram showing how to intentionally generate a place where the formation of frozen soil is delayed Diagram showing how to intentionally generate a place where the formation of frozen soil is delayed The figure which shows the method of constructing the frozen earth system impermeable wall 63 continuously with the impermeable wall of the steel pipe sheet pile 51 The figure which shows the method of constructing the frozen soil system impermeable wall 75 continuously with the impermeable wall of the steel sheet pile 65

  Hereinafter, a first embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram showing each process for creating a frozen soil type water-impervious wall 27. FIG. 1A is a diagram showing a process of installing the freezing tube 1 and the temperature measuring tube 7 on the ground 2, FIG. 1B is a diagram showing a process of forming the prior frozen soil 17, and FIG. FIG. 1D is a diagram showing a process of forming the frozen ground 23. FIG.

  FIG. 2 is a diagram showing a vertical section of the ground 2, FIG. 3 is an example of a graph showing the relationship between the number of days of freezing operation and temperature, and FIG. 4 is a flowchart of a method for creating a frozen soil type impermeable wall 27. FIG. Hereinafter, the construction method of the frozen soil type impermeable wall 27 will be described with reference to the flowchart shown in FIG.

  In order to create the frozen soil type water-impervious wall 27, first, prior freezing is performed (step 101). In step 101, as shown in FIG. 1A, a plurality of freezing tubes 1 are installed on the freezing tube arrangement line 5 of the ground 2. The plurality of freezing tubes 1 are installed at a predetermined interval 3. However, in the place where the obstacle 9 exists in the ground 2, the freeze tube 1 a is installed with the obstacle 9 interposed therebetween, and therefore the interval 3 a between the freeze tubes 1 a is larger than the predetermined interval 3. As shown in FIG. 2, the freezing tube 1 reaches the impermeable layer 13 at the lower end.

  A plurality of temperature measuring tubes 7 are installed in parallel with the freezing tube arrangement line 5. The temperature measuring tube 7 is installed, for example, on the upstream side of the groundwater flow from the freezing tube arrangement line 5. It is assumed that the temperature measuring tube 7 has a distance between the freezing tube arrangement line 5 and the temperature measuring tube 7 smaller than the assumed freezing radius of the freezing tube 1 or the interval 3 where the freezing tube 1 is installed in a plan view. The temperature measuring tube 7 is arrange | positioned at the water-permeable layer 11, as shown in FIG. For example, an optical fiber sensor is disposed in the temperature measuring tube 7, and the temperature is measured at the temperature measuring location 15. The temperature measuring points 15 are set, for example, at intervals of 1 m, and temperature management is performed with an average value for each 1 m.

  For example, when the interval 3 between the freezing tubes 1 is 1 m and the radius of the frozen soil formed around each freezing tube 1 is planned to be 1 m, the distance between the temperature measuring tube 7 and the freezing tube arrangement line 5 is If it is set to 85 cm and the temperature measuring tubes 7 are arranged at intervals of 5 m, it is possible to detect the temperature difference.

  In step 101, after installing the freezing tube 1 and the temperature measuring tube 7 on the ground 2 as shown in FIG. 1 (a), the place where the freezing tube 1 is installed is larger than the predetermined interval 3, that is, the freezing tube 1a is installed. Prior freezing of the places installed at the interval 3a across the obstacle 9 is performed. By performing prior freezing using the freezing pipe 1a, the prior frozen soil 17 is formed on the ground 2 near the obstacle 9 as shown in FIG.

  After step 101, the whole is frozen (step 102), and the date of completion of freezing is predicted (step 103). In step 102, the remaining freeze tubes 1 are used to freeze the places where the freeze tubes 1 are installed at a predetermined interval 3. It should be noted that the start of step 102 may be before the completion of the preceding frozen soil 17 as long as a sufficient time has passed since the start of the preceding freezing in step 101.

  In step 103, the remaining number of days until the underground temperature reaches the target value is estimated from the temperature decreasing tendency in a predetermined period of the time curve of the temperature measured using the temperature measuring tube 7. In step 103, the freezing completion date is predicted from the time curve for the plurality of temperature measuring points 15 (FIG. 2) of each temperature measuring tube 7, and the remaining days from the present to the freezing completion date are calculated. Then, the maximum value of the number of remaining days of the plurality of temperature measuring locations 15 is estimated as the number of remaining days at the position of the temperature measuring tube 7.

  A temperature aging curve 29 is generally as shown in FIG. In order to predict the freezing completion date from the temperature curve 29 of the graph shown in FIG. 3, the period of 13 to 20 days of freezing operation is set as the period of interest. In addition, the target value of the underground temperature is set to 0 ° C. Then, using the straight line 33 obtained by halving the gradient of the straight line 31 indicating the average temperature decrease rate during the period of interest, the number of days 35 at which the temperature of the straight line 33 reaches the target value of 0 ° C. is predicted as the freezing completion date. Then, the remaining number of days from the present to the predicted completion date of freezing is calculated.

  When predicting the completion date of freezing, the target period of the time curve 29 is not limited to the 13th to 20th, and the target value of the underground temperature is not limited to 0 ° C. Further, the gradient of the straight line used for the evaluation is not limited to ½ times the gradient of the straight line 31 indicating the average temperature decrease rate during the period of interest. However, if these values are used, the predicted freezing completion date is almost never earlier than the actual freezing completion date 34, and the safety evaluation can be performed.

  As shown in FIG. 1 (c), the frozen soil 19 is formed almost entirely on the freezing pipe arrangement line 5 by the step 102, but the formation of frozen soil is delayed at the location where the groundwater flow is concentrated as shown by the arrow A. The unclosed location 21 is generated. The position of the unclosed location 21 is predicted by step 103.

  After step 103, the auxiliary construction method is started (step 104). In step 104, first, an unclosed portion 21 to which an auxiliary construction method for promoting freezing is applied is determined according to the remaining number of days predicted in step 103. For example, the auxiliary construction method may be applied to a place where the remaining days are equal to or greater than the allowable number of days, or the auxiliary construction method may be applied to a place where freezing is relatively slow.

  Then, the follow-up frozen soil 23 is formed as shown in FIG. 1D by applying the auxiliary construction method for promoting freezing to the unclosed portion 21 determined to apply the auxiliary construction method. As the auxiliary construction method, for example, reduction of the groundwater flow velocity by injecting chemical solution upstream of the groundwater flow, additional installation of freezing pipes, pumping of water upstream of the groundwater flow, water injection downstream, and the like can be considered. When the auxiliary construction method is applied, a temperature measuring tube 25 (FIG. 1 (d)) is added adjacent to the freezing tube 1b of the unclosed portion 21 (FIG. 1 (c)) where the freezing is delayed. You may grasp | ascertain the formation condition of the following frozen ground 23. FIG.

  After step 104, the completion of creation is confirmed (step 105). In step 105, it is confirmed whether or not the creation of the frozen soil type water-impervious wall 27 is completed. As shown in FIG. 1 (d), when the frozen ground 23 is formed in the unclosed portion 21 (FIG. 1 (c)) and the creation of the frozen soil-type impermeable wall 27 is completed, after the final confirmation, The process proceeds to maintenance management (step 106). If not completed, the process returns to step 104.

  Thus, according to the first embodiment, when installing a plurality of freezing tubes 1 on the freezing tube arrangement line 5 of the ground 2, a place where the installation interval 3 a of the freezing tubes 1 is larger than the predetermined interval 3 is selected. By providing and forming the pre-frozen soil 17 at that location, it is possible to reliably close the location where the formation of frozen soil is likely to be delayed.

  In addition, the number of days until the underground temperature reaches the target value is estimated from the temperature decrease tendency of the time curve 29 of the temperature measured using the temperature measuring tube 7 installed adjacent to the freezing tube arrangement line 5. By doing so, it is possible to grasp the formation status of the frozen soil 19, predict in advance the location where the frozen soil 19 is difficult to close, and appropriately determine the location where the freezing promotion measures should be taken. And by implementing the auxiliary construction method for freezing promotion measures in the unclosed location 21, it is possible to reliably form the subsequent frozen soil 23 at an early stage and to create the frozen soil-type impermeable wall 27.

  Furthermore, if the temperature measuring pipe 25 is added adjacent to the unclosed location 21 where the formation of frozen soil is delayed, it is easy to grasp the formation status of the subsequent frozen soil 23. By setting the distance between the freezing tube arrangement line 5 and the temperature measuring tube 7 and the temperature measuring tube 25 to be smaller than the expected freezing radius of the freezing tube 1 or the predetermined installation interval 3 of the freezing tube 1 in plan view, frozen soil is formed. The temperature of the inside ground 2 can be measured appropriately.

  In the first embodiment, as shown in FIG. 4, the auxiliary construction method for promoting freezing was started before confirming the completion of the construction of the frozen soil type water shielding wall 27. The creation procedure is not limited to this.

  FIG. 5 is a view showing a flowchart of another method for creating the frozen soil type water shielding wall 27. The creation method shown in FIG. 5 is almost the same as the creation method shown in FIG. 4, but after the completion date of freezing is predicted in step 103, the completion of creation is confirmed in step 107. If the frozen soil type water-impervious wall 27 is completed, the process proceeds to maintenance after the final confirmation (step 109). If the frozen soil type water-impervious wall 27 is not completed and there is an unclosed portion 21 as shown in FIG. 1C, the auxiliary construction method is started (step 108), and then the process returns to step 107.

  In the first embodiment, the temperature measuring tube 7 and the temperature measuring tube 25 are installed to grasp the formation status of the frozen soil 19 and the succeeding frozen soil 23. However, the temperature measuring tube 7 and the temperature measuring tube 25 are installed as follows. Not required. An auxiliary construction method for promoting freezing may be applied to a location where the formation of the frozen soil 19 is delayed without predicting the unclosed location 21 using the temperature measuring tube 7.

  Next, a second embodiment will be described. FIG. 6 is a diagram illustrating a method for intentionally generating a location where the formation of frozen soil is delayed. In the second embodiment, the frozen soil type impermeable wall construction method is substantially the same as in the first embodiment. However, in the second embodiment, the frozen soil is intentionally formed when the entire freezing is performed. The place where is delayed is generated.

  In the second embodiment, when the entire freezing is performed in step 102 shown in FIG. 4, as shown in FIG. 6, the operation of some freezing pipes 1c is delayed and the formation of frozen soil is delayed. The part 39 is selectively generated at an arbitrary position. Thereby, as shown by the arrow B, the flow path of groundwater is ensured and the frozen soil 37 of another location is formed reliably.

  Then, after Step 103, at an appropriate time, the freezing pipe 1c is operated to form a post-frozen soil at the unclosed portion 39 and the frozen soil 37 is closed. Or, an auxiliary method such as chemical injection is implemented. If it is determined in step 103 that there is an unclosed location that has occurred unintentionally in addition to the unclosed location 39, the auxiliary construction method is started in step 104. And the frozen soil 37 is closed, and a frozen soil system impermeable wall is completed.

  Next, a third embodiment will be described. FIG. 7 is a diagram showing a method for intentionally generating a location where the formation of frozen soil is delayed. FIG. 7A is a diagram illustrating a process of forming the frozen soil 41, and FIG. 7B is a diagram illustrating a process of forming the subsequent frozen soil 47. The construction method of the frozen soil type impermeable wall in the third embodiment is almost the same as that in the first embodiment. However, in the third embodiment, the frozen soil is intentionally formed when the entire freezing is performed. The place where is delayed is generated.

  In the third embodiment, when a plurality of freezing tubes 1 are installed on the freezing tube arrangement line 5 of the ground 2 in order to perform prior freezing in step 101 shown in FIG. 4, as shown in FIG. Furthermore, not only the interval 3a between the freezing tubes 1a for forming the preceding frozen soil 17 but also the interval 3b between the freezing tubes 1d is set to be larger than the predetermined interval 3. The installation position of the freezing tube 1d is arbitrary.

  Then, after the step 101, when the entire freezing is performed in the step 102, the formation of frozen soil is delayed where the interval 3b between the freezing tubes 1d is larger than the predetermined interval 3 as shown in FIG. An unclosed portion 43 is generated. In step 102, the unclosed portion 43 becomes a groundwater flow path, so that the frozen soil 41 in other portions is reliably formed.

  Next, after step 103, at an appropriate time, by using the temperature measuring tube 7 of the unclosed portion 43 shown in FIG. 7 (a) as a freezing tube, the unclosed portion 43 is shown in FIG. 7 (b). The frozen soil 47 is formed. At this time, a new temperature measuring tube 45 is installed to a necessary depth, and the formation status of the subsequent frozen soil 47 is grasped. If it is determined in step 103 that there is an unclosed location that has occurred unintentionally in addition to the unclosed location 43, an auxiliary construction method is started in step 104. Then, the frozen soil 41 is closed, and the frozen soil-type impermeable wall 49 is completed.

  In the second and third embodiments, the operation of the freezing pipe 1c is delayed, or a place where the installation interval 3b of the freezing pipe 1d is wide is provided in advance separately from the place where the preceding frozen ground 17 is formed. By intentionally generating a place where formation is delayed, it is possible to secure a passage for groundwater and to easily form frozen soil in other parts. In addition, by intentionally delaying the formation of frozen soil, it is possible to predict in advance where the frozen soil is difficult to close, and to quickly take measures to promote freezing.

  In the third embodiment, when the unclosed portion 43 where the formation of frozen soil is delayed is frozen, the existing temperature measuring tube 7 is used as a freezing tube, and a new temperature measuring tube 45 is added adjacently. Thus, the follow-on frozen soil 47 can be formed at an early stage while grasping the formation status of the frozen soil.

  In the second and third embodiments, the installation of the temperature measuring tube 7 and the temperature measuring tube 45 is not essential. Without predicting the unclosed location using the temperature measuring tube 7, the auxiliary construction method for promoting freezing was applied to the location where the formation of frozen soil was unintentionally delayed, and the formation of frozen soil was intentionally delayed Follow-up frozen soil may be formed at the location.

  Next, a fourth embodiment will be described. FIG. 8 is a view showing a method of creating a frozen soil type water shielding wall 63 continuously with the water shielding wall of the steel pipe sheet pile 51. FIG. 8A is a diagram illustrating a process of installing the freezing pipes 53 and 55, and FIG. 8B is a diagram illustrating a process of completing the frozen soil type water-impervious wall 63.

  In order to create the frozen soil type water shielding wall 63 continuously with the water shielding wall of the steel pipe sheet pile 51 installed on the ground 62, first, as shown in FIG. 8A, the water shielding of the steel pipe sheet pile 51 in plan view. A plurality of first freezing tubes 53 are installed on the wall extension. Moreover, the freezing pipe 55 which is a 2nd freezing pipe is installed in the steel pipe 51a of the edge part of the steel pipe sheet pile 51. FIG. The space | interval 59 of the freezing tube 53a adjacent to the steel pipe sheet pile 51 and the freezing tube 55 among the several freezing tubes 53 is smaller than the installation space | interval 57 between the freezing tubes 53. FIG.

  Next, the freezing pipe 53a and the freezing pipe 55 are operated, and as shown in FIG.8 (b), the prior frozen soil 61 containing the edge part of the steel pipe sheet pile 51 is formed. Thereafter, the other freezing pipe 53 is operated to form frozen soil that is continuous with the preceding frozen soil 61, and the creation of the frozen soil-type impermeable wall 63 is completed.

  The water-impervious wall of the steel pipe sheet pile 51 in the fourth embodiment generally has a higher thermal conductivity than the ground 62. Therefore, the interval 59 between the freezing pipe 53a provided on the extension of the water shielding wall of the steel pipe sheet pile 51 in plan view and the freezing pipe 55 provided in the steel pipe 51a at the end of the steel pipe sheet pile 51 is set to a frozen earth type shield. If it is made smaller than the space | interval 57 between the some freezing pipes 53 provided in order to create the water wall 63, between the water-impervious wall of the steel pipe sheet pile 51 and the frozen soil system water-impervious wall 63 is surely frozen, and the steel pipe A frozen soil type water shielding wall 63 can be formed continuously with the water shielding wall of the sheet pile 51.

  In the fourth embodiment, the water shielding wall of the steel pipe sheet pile 51 is illustrated as the other type of water shielding wall. However, the steel sheet pile, concrete, and mortar having higher thermal conductivity than the ground are used for the other type of water shielding wall. A frozen water system impermeable wall may be formed continuously with another type of impermeable wall by a method similar to that of the fourth embodiment.

  FIG. 9 is a view showing a method for creating a frozen soil type water shielding wall 75 continuously with the water shielding wall of the steel sheet pile 65. In the example shown in FIG. 9, in order to construct the frozen soil type water shielding wall 75 continuously to the water shielding wall of the steel sheet pile 65 installed on the ground 72, first, as shown in FIG. A plurality of first freezing pipes 67 are installed on the extension of 65 impermeable walls. Moreover, the freezing pipe 69 which is a 2nd freezing pipe is installed adjacent to the water impervious wall of the steel sheet pile 65 in parallel in plan view. Among the plurality of freezing tubes 67, the interval 73 between the freezing tube 67 a adjacent to the steel sheet pile 65 and the freezing tube 69 is smaller than the installation interval 71 between the freezing tubes 67.

  Next, the freezing pipe 67a and the freezing pipe 69 are operated, and the preceding frozen soil including the end part of the steel sheet pile 65 is formed. Thereafter, the other freezing pipe 67 is operated to form frozen soil that is continuous with the preceding frozen soil, and the creation of the frozen soil type water-impervious wall 75 is completed.

  In the fourth embodiment or the example shown in FIG. 9, the first frozen pipe and the second frozen pipe are operated, and the preceding frozen soil is connected to the connecting portion between the other type of impermeable wall and the frozen soil type impermeable wall. Although the other freezing tubes were operated after forming, all the freezing tubes may be operated simultaneously. If the impermeable wall of another method is made of a material having a higher thermal conductivity than the ground, and the distance between the first freezing pipe and the second freezing pipe is smaller than the distance between the other freezing pipes, Even if the freezing pipes are operated at the same time, the connecting portion between the other type of impermeable wall and the frozen soil type impermeable wall can be reliably frozen in advance.

  As mentioned above, although embodiment of this invention was described referring an accompanying drawing, the technical scope of this invention is not influenced by embodiment mentioned above. It is obvious for those skilled in the art that various modifications or modifications can be conceived within the scope of the technical idea described in the claims, and these are naturally within the technical scope of the present invention. It is understood that it belongs.

1, 1a, 1b, 1c, 1d, 53, 53a, 55, 67, 67a, 69 ......... Freezing tube 3, 3a, 3b, 57, 59, 71, 73 ......... Interval 5 ......... Freezing tube arrangement Lines 7, 25, 45 ......... Temperature measuring tube 15 ......... Temperature measurement point 17, 61 ......... Pre-frozen soil 19, 37, 41 ......... Frozen soil 21, 39, 43 ......... Unclosed point 23, 47 ......... Frozen frozen soil 27, 49, 63, 75 ......... Frozen soil type impermeable wall 29 ......... Time curve 51 ... …… Steel sheet pile 65 ... …… Steel sheet pile

Claims (8)

A step of installing a plurality of freezing pipes on the freezing pipe arrangement line of the ground; and
Forming a pre-frozen soil at a location where the installation interval of the freezing pipes is larger than a predetermined interval; and
A step c of forming frozen soil at a place where the installation interval of the freeze tubes is a predetermined interval;
A method for constructing a frozen soil type water-impervious wall characterized by comprising:   The method for constructing a frozen soil type impermeable wall according to claim 1, wherein an auxiliary construction method for promoting freezing is applied to a location where formation of frozen soil is delayed in the step c. Prior to the step c, a plurality of temperature measuring tubes are installed in parallel with the cryotube arrangement line,
In step c, the number of days remaining until the underground temperature reaches the target value is estimated from the temperature decreasing tendency of the temperature curve measured using the temperature measuring tube in a predetermined period, and frozen according to the number of days remaining. The construction method of the frozen soil system impermeable wall according to claim 2, wherein a location where an auxiliary construction method for promotion is applied is determined. In the step c, a place where the formation of frozen soil is delayed intentionally,
The frozen soil type water-impervious structure according to any one of claims 1 to 3, further comprising a step d of forming subsequent frozen soil at a location where formation of the frozen soil is delayed after the step c. How to build a wall.   The method for creating a frozen soil-type impermeable wall according to claim 2 or 4, wherein a temperature measuring tube is added adjacent to a location where the formation of the frozen soil is delayed.   The frozen soil system according to claim 3 or 5, wherein a distance between the freezing tube arrangement line and the temperature measuring tube is smaller than an assumed freezing radius of the freezing tube or the predetermined interval in a plan view. Construction method of impermeable walls. A frozen soil type impermeable wall constructed continuously with other type impermeable walls,
A first freezing pipe provided on an extension of the other type of water shielding wall in a plan view, and a second freezing pipe provided in parallel and adjacent to the other type of water shielding wall in a plan view. A method for constructing a frozen soil system impermeable wall, characterized in that an interval is smaller than an installation interval of a plurality of freezing pipes provided for constructing the frozen soil system impermeable wall.   8. The construction of a frozen soil type impermeable wall according to claim 7, wherein the other type of impermeable wall is a steel pipe sheet pile, and the second frozen pipe is provided in a steel pipe at an end of the steel pipe sheet pile. Method.

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