JP2003286725A - Immersion method of caisson - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an immersion method of a caisson for preventing excessive settlement of the caisson by enabling construction of the caisson even when a support ground is weak. <P>SOLUTION: In the immersion method of the caisson 1, a necessary number of SMWs 6 with prescribed strength is installed with a non-core material in a range 5 corresponding to the lower part of a cutting edge of the caisson 1, and thereafter the caisson 1 is set on SMW 6 to excavate a ground 2 and SMW 6 so as to lower a support force 7. Thereby even when the support ground is weak, construction of the caisson is enabled, and constant support force is always secured, so that the excessive settlement is prevented, and stabilization of immersion working is contrived to facilitate construction period management. <P>COPYRIGHT: (C)2004,JPO

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for laying a caisson that can be carried out reliably even when the supporting ground is unstable such as a soft ground. 2. Description of the Related Art As shown in a schematic diagram of FIG. 2, a caisson is laid down by placing a caisson 1 previously constructed on the ground on a supporting ground 2 and excavating a lower portion 3 of the caisson. 4, the sinking of the caisson 1 is greatly affected by the condition of the supporting ground 2 because the sinking of the caisson 1 is caused by sinking into the ground by its own weight or load while reducing the number of the ground. [0003] In particular, when the supporting ground 2 is soft ground,
In some cases, construction may not be possible due to lack of bearing capacity 4, and accidents due to excessive subsidence during construction may occur. It is common to set up. [0004] However, even with such a construction plan, the distribution of the geology constituting the supporting ground 2 cannot be completely grasped, so that the planned supporting capacity may not be obtained. . And even if it was as planned, the bearing capacity will change variously with the change of geology during subsidence, and as a result, high construction management capability is required at present. It is. SUMMARY OF THE INVENTION The present invention has been made in view of the above situation, and enables the construction of a caisson even if the supporting ground is soft ground, and allows the caisson to be installed. It provides a caisson squatting method that can also prevent subsidence. A caisson laying method according to the present invention comprises a step of forming a continuous wall (hereinafter, referred to as SMW) of a cement-free material having a predetermined strength in a region corresponding to a lower portion of a cutting edge of a caisson. The required number is installed, and after that, the caisson is set on the SMW and the ground and the SMW are excavated to reduce the supporting force, thereby making it possible to construct the caisson even if the supporting ground is soft ground. , By maintaining a constant bearing capacity to prevent oversinking,
It stabilizes the laying work and facilitates construction period management. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A caisson squatting method according to the present invention is as follows. First, in a range corresponding to a lower portion of a blade of a caisson to be sunk, a required number of coreless SMWs having a predetermined strength are provided. The caisson is set on this SMW, and at the same time, the supporting ground of the caisson is lowered by excavating the supporting ground and the installed SMW by the same method as before, As a result, it is possible to constantly and stably perform the laying work, and the management of the total construction period is facilitated by specifying the construction period secured by stabilizing the construction state. An embodiment of a caisson laying method according to the present invention will be described below in detail with reference to the drawings. In order to facilitate understanding of the present invention, the same parts as those in the related art are denoted by the same reference numerals. FIG. 1 shows an embodiment of a caisson laying method according to the present invention. FIG. 1 (a) is a plan view showing an arrangement state of SMWs and FIG. 1 (a) is viewed from arrows (b)-(b). This is represented by a sectional view (b). In this embodiment, a caisson 1 is constructed on the ground and installed on the supporting ground 2 in order to construct a skeleton. However, as shown in FIG. The SMW 6 is constructed in advance in a range 5 corresponding to the position where the lower part of the blade is installed, and is installed as a load support for the caisson 1. [0011] The SMW 6 is constructed without using a core material such as H steel, and the soil cement is formulated to have a strength or less so as not to hinder the excavation below the cutting edge of the caisson 1. The number of SMWs 6 is determined in accordance with the weight of the caisson 1 by using the above-described SMW 6, and the required number of SMWs 6 are installed at predetermined intervals in accordance with the required supporting force. The caisson 1 is installed so as to be mounted on the group of the SMW 6 after the SMW 6 is installed, so that the entire load or a part thereof is supported by the SMW 6. Therefore, the caisson 1 is installed on the supporting ground 2 in a stabilized state even if the supporting ground 2 is soft ground. FIG. 1B shows a state in which the caisson 1 is supported by the SMW 6. In the present embodiment, even if the supporting ground 2 is soft ground, the caisson 1
Since they are placed on the groups 6 and 6, the supporting force 7 is sufficiently ensured, and they are constantly supported without causing insufficient supporting force. Therefore, when the caisson 1 is laid down,
By using a heavy machine while excavating in the same manner as before, it is possible to continuously reduce the supporting force by breaking the SMW 6 and the supporting ground 2 below the cutting edge, and the work of submerging the caisson 1 does not hinder any kind. We can proceed smoothly without receiving it. As described above, the caisson laying method according to the present invention is configured as in the embodiment, so that there is no concern that the caisson laying work cannot be performed, and Since there is no accident due to subsidence, there is no need to conduct a drilling survey in advance to prevent these accidents, and in addition, if the bearing capacity changes due to geological changes during subsidence, This does not cause any trouble, and as a result, the construction management is made reliable and easy. As described above, the caisson squatting method according to the present invention has been described in detail based on the above embodiments. However, the present invention is not limited to these embodiments at all and departs from the gist of the invention. It goes without saying that various changes are possible within a range not to be performed. According to the method of laying a caisson according to the present invention, a required number of coreless SMWs having a predetermined strength are installed in the area corresponding to the lower part of the blade of the caisson, and then the caisson is set on the SMW. To reduce the bearing capacity by excavating the ground and SMW, thereby enabling caisson construction even when the supporting ground is soft ground, and preventing over-subsidence by constantly securing a constant bearing force This has the effect of stabilizing the laying work and facilitating construction period management.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an embodiment of a caisson laying method according to the present invention. FIG. 2 is a schematic diagram of a conventional caisson laying method. [Description of symbols] 1 caisson, 2 supporting ground, 3 caisson Lower part, 4, 7 Supporting force, 5 Range of lower part of cutting edge, 6 S
MW,

Claims (1)

Claims: 1. A required number of soil-cement continuous walls made of a coreless material having a predetermined strength are installed in an area corresponding to a lower portion of a blade of a caisson, and thereafter, a caisson is placed on the soil-cement continuous wall. A caisson laying method that lowers the bearing capacity by excavating the ground and soil cement continuous wall by setting.