Bottom sealing construction method in sinking well
Technical Field
The invention relates to the technical field of open caisson construction, in particular to a bottom sealing construction method in an open caisson.
Background
The large-volume open caisson foundation has the characteristics of large plane size, deep sinking depth and large bottom sealing square amount, and because the sinking depth is deep, a non-drainage sinking mode is usually adopted in the last sinking, the bottom sealing quality of the open caisson is difficult to control, the bottom sealing concrete square amount is large, the underwater concrete pouring construction organization is difficult, and the tensile and bending resistance of underwater plain concrete is poor.
Therefore, there is a need for a bottom sealing construction method in a caisson that can solve the above problems.
Disclosure of Invention
The invention aims to provide a bottom sealing construction method in a sinking well according to the defects of the prior art, wherein a bottom compartment is arranged at the bottom in the sinking well, the bottom compartment and the bottom of the sinking well are jointly enclosed to divide a bottom sealing space into a plurality of parts, a cavity of the bottom compartment is filled with casting concrete, and then the divided bottom sealing spaces are filled with casting concrete in sequence to form a bottom seal, so that the tensile and bending resistance of the bottom seal is effectively improved.
The purpose of the invention is realized by the following technical scheme:
a bottom sealing construction method in a sinking well is characterized by comprising the following steps:
(S1) placing tunneling equipment in the open caisson, and tunneling the tunneling equipment downwards to a designed elevation along the bottom of the open caisson;
(S2) retrieving the tunnelling equipment from within the open caisson, the open caisson being sunk to a tunnelling floor level under the suspension of a suspension system;
(S3) lowering the bottom compartment by using the hanging system, wherein the inner wall of the bottom of the open caisson is provided with guide grooves with the number, the position, the shape and the size corresponding to those of the outer end part of the bottom compartment in the circumferential direction, the guide grooves move downwards along the guide grooves through the outer end part of the bottom compartment to realize the lowering of the bottom compartment, and a rotating groove is arranged below the guide grooves and communicated with the lower ends of the guide grooves;
(S4) when the bottom compartment is put down in place, rotating the bottom compartment through the hanging system to make the bottom compartment staggered with the guide groove;
(S5) the bottom compartment and the bottom of the open caisson are enclosed together to divide the bottom sealing space into a plurality of spaces, pouring concrete is filled in the cavity of the bottom compartment, and then the divided bottom sealing spaces are filled with the pouring concrete in sequence to form a bottom seal;
(S6) after the back cover reaches the design strength, the hanging system is dismantled, water in the caisson is extracted, and the caisson construction is completed.
The guide groove is internally provided with a bulge, and the outer end part of the bottom compartment is provided with a groove matched with the bulge.
The number of the rotary grooves corresponds to the number of the outer end parts of the bottom compartment, a plurality of tooth openings are arranged between the rotary grooves along the vertical direction, and the tooth openings are communicated with the side parts of the rotary grooves.
The bottom of the bottom compartment is provided with a pointed end.
The bottom compartment is in a cross shape or a groined shape.
And shear keys are arranged on the side surfaces of the bottom compartments.
The invention has the advantages that:
(1) the method is simple, and the tensile and bending resistance of the back cover is effectively improved;
(2) in order to ensure the stability of the foundation pit, the open caisson in the soft soil area needs to adopt a non-drainage excavation mode, the reinforced concrete bottom compartment divides the bottom sealing concrete into a plurality of parts under water, and single-compartment pouring is carried out, so that the single-time pouring volume of the concrete is reduced, and the pouring quality of the bottom sealing concrete is favorably improved;
(3) the bottom compartment is provided with a shear key, so that the bottom compartment can be more firmly connected with bottom sealing plain concrete;
(4) the open caisson bottom section is provided with the tooth openings, the connection condition of the back cover and the open caisson is closer to consolidation, and the bending moment coefficient of the round back cover concrete can be reduced;
(5) the bottom compartment is a steel structure, has strong tensile and bending resistance, and can be used for bending resistance together with the bottom sealing concrete, thereby obviously improving the bending resistance, reducing the thickness of the bottom sealing concrete and reducing the construction difficulty.
Drawings
FIG. 1 is a longitudinal cross-sectional view of an open caisson of the invention;
FIG. 2 is a cross-sectional view of the open caisson of the present invention;
FIG. 3 is a longitudinal sectional view of the open caisson in step S1 of the construction method of the present invention;
fig. 4 is a cross-sectional view of the open caisson in step S1 of the construction method of the present invention;
FIG. 5 is a longitudinal sectional view of the open caisson in step S2 of the construction method of the present invention;
fig. 6 is a cross-sectional view of the open caisson in step S2 of the construction method of the present invention;
FIG. 7 is a longitudinal sectional view of the open caisson in step S3 of the construction method of the present invention;
fig. 8 is a cross-sectional view of the open caisson in step S3 of the construction method of the present invention;
fig. 9 is a longitudinal sectional view of the open caisson in step S4 of the construction method of the present invention;
fig. 10 is a cross-sectional view of the open caisson in step S4 of the construction method of the present invention;
fig. 11 is a longitudinal sectional view of the open caisson in step S5 of the construction method of the present invention;
fig. 12 is a cross-sectional view of the open caisson in step S5 of the construction method of the present invention;
fig. 13 is a longitudinal sectional view of the open caisson in step S6 of the construction method of the present invention;
fig. 14 is a cross-sectional view of the open caisson in step S6 of the construction method of the present invention;
fig. 15 is a layout view of the guide groove, the rotary groove and the tooth gap of the present invention.
Detailed Description
The features of the present invention and other related features are described in further detail below by way of example in conjunction with the following drawings to facilitate understanding by those skilled in the art:
as shown in fig. 1-15, the marks 1-14 are respectively indicated as ground line 1, water level 2, open caisson 3, back cover 4, bottom compartment 5, tunneling equipment 6, bearing platform 7, guide groove 8, shear key 9, protrusion 10, groove 11, tooth mouth 12, tip 13 and rotary groove 14.
Example (b): as shown in fig. 1 to 15, the present embodiment relates to a bottom sealing construction method in a caisson, which comprises the following steps:
s1: as shown in fig. 3 and 4, a tunneling device 6 is placed in the open caisson 3, the tunneling device 6 extends into the open caisson 3 below the water level 2, and the tunneling device 6 tunnels downwards along the bottom of the open caisson 3 to reach the designed elevation. The open caisson 3 is provided inside a bearing platform 7, and the bearing platform 7 is provided on the ground line 1.
S2: as shown in fig. 5 and 6, the cutterhead of the excavating equipment 6 is contracted, the excavating equipment 6 is lifted, and the open caisson 3 is suspended by a suspension system and then sinks to the excavating bottom elevation.
S3: as shown in fig. 7 and 8, the bottom compartment 5 is lowered by means of a suspension system. The bottom compartment 5 is cross-shaped or # -shaped, in the embodiment, the bottom compartment 5 is cross-shaped, the bottom of the bottom compartment is arc-shaped, so that the requirement of forming a circular back cover is met, a cavity is arranged in the bottom compartment 5, namely, the bottom compartment 5 is only provided with an open top, other places are closed, and a reinforced concrete structure can be formed by filling concrete into the cavity from the top of the bottom compartment 5. The inner wall of the bottom of the open caisson 3 is provided with guide grooves 8 (four in the embodiment) corresponding to the outer end parts of the bottom compartments 5 in number, position, shape and size along the circumferential direction, the guide grooves 8 move downwards along the guide grooves 8 through the outer end parts of the bottom compartments 5 to realize the downward placement of the bottom compartments 5, and in addition, guide wheels (not shown) are installed at the end parts of the bottom compartments 5 to be beneficial to the smooth downward placement of the bottom compartments 5. Be equipped with arch 10 in the guide way 8, end compartment 5 outer tip is seted up with protruding 10 matched with recess 11, and protruding 10 and recess 11 cooperation for accurate location between end compartment 5 and guide way 8. In addition, the bottom of the bottom compartment 5 is provided with a pointed end 13, and the pointed end 13 can be penetrated into a soft soil body below the bottom of the open caisson 3 under the action of self gravity.
S4: as shown in fig. 9, 10 and 15, a rotary groove 14 is provided below the guide groove 8, the rotary groove 14 communicates with the lower end of the guide groove 8, and the size of the rotary groove 14 is larger than that of the guide groove 8. When the bottom compartment 5 is put down in place, the bottom compartment 5 is rotated by the hanging system, so that the bottom compartment 5 is staggered with the guide groove 8, namely when the outer end part of the bottom compartment 5 completely enters the rotating groove 14, the bottom compartment 5 is rotated by the hanging system, so that the outer end part of the bottom compartment 5 is far away from the guide groove 8, and the bottom compartment is fixed at the bottom of the open caisson 3.
S5: as shown in fig. 11, 12 and 15, the bottom compartment 5 and the bottom of the open caisson 3 jointly enclose to divide the bottom sealing space into a plurality of small bottom sealing spaces (four in this embodiment), the cavity of the bottom compartment 5 is filled with cast concrete, and then the divided bottom sealing spaces are filled with cast concrete in sequence to form the bottom sealing 4. In order to ensure the stability of the foundation pit, the open caisson in the soft soil area needs to adopt a non-drainage excavation mode, the bottom sealing concrete is divided into a plurality of parts by the reinforced concrete bottom compartment under water, and single-compartment pouring is carried out, so that the single-time pouring volume of the concrete is reduced, and the pouring quality of the bottom sealing concrete is favorably improved. In this embodiment, the number of the rotary grooves 14 (four in this embodiment) corresponds to the number of the outer end portions of the bottom compartments 5, the rotary grooves 14 are arranged along the circumferential direction of the inner wall of the bottom of the open caisson 3, a plurality of tooth openings 12 (two in this embodiment) are arranged between two adjacent rotary grooves 14 and arranged along the vertical direction, the tooth openings 12 are arranged along the circumferential direction of the inner wall of the bottom of the open caisson 3, the tooth openings 12 are communicated with the side portions of the rotary grooves 14, the connection condition of the bottom seal 4 and the open caisson 3 can be closer to consolidation through the tooth openings 12, and the bending moment coefficient of circular bottom seal concrete can be reduced. In addition, the side surface of the bottom compartment 5 is provided with a shear key 9 which can be more firmly connected with the bottom sealing plain concrete.
S6: as shown in fig. 13 and 14, after the back cover 4 reaches the designed strength, the hanging system is removed, and the water in the open caisson 3 is extracted, thereby completing the open caisson construction.
In the embodiment, the bottom compartment is of a steel structure and has strong tensile and bending resistance, the bottom compartment and the bottom sealing concrete jointly participate in bending resistance, the bending resistance can be obviously improved, the thickness of the bottom sealing concrete is reduced, the construction difficulty is reduced, and the bottom sealing thickness of the bottom compartment can be reduced by one third compared with that of a bottomless compartment under the same condition.
In summary, in the embodiment, the open caisson is not drained, tunneled and excavated, due to the existence of the tunneling equipment, the bottom compartment needs to be installed by being placed downwards after the tunneling equipment is dismantled, and the open caisson, the bottom compartment and the bottom sealing concrete are connected by adopting targeted measures, so that the open caisson is innovative.
Although the conception and the embodiments of the present invention have been described in detail with reference to the drawings, those skilled in the art will recognize that various changes and modifications can be made therein without departing from the scope of the appended claims, and therefore, they are not to be considered repeated herein.