CN216515676U - Steel sheet pile cofferdam structure of deep silt geology closes on structure - Google Patents

Abstract

The utility model discloses a steel sheet pile cofferdam structure of a deep silt geology near structure, which comprises steel sheet piles, enclosing purlins, steel pipe diagonal braces, cement mixing piles and concrete cushion layers, wherein the steel sheet piles are arranged on the enclosing purlins; the steel sheet pile is used as a structure for resisting the pressure of a soil body and stopping water; the enclosing purlin, the steel pipe diagonal brace and the steel pipe diagonal brace are connected into a whole through welding and serve as an inner supporting force structure to bear horizontal thrust transmitted by the steel sheet pile; the cement mixing pile is arranged inside the enclosing purlin and used for pre-treating soil below a reinforcing base in advance; the concrete cushion layer is arranged at the upper end of the cement mixing pile and used as a base construction working platform and participates in partial stress, the cement mixing pile is fully utilized to reinforce the base sludge, the length of the steel plate pile is effectively reduced by more than 30%, the steel plate pile is transported in whole section and is inserted and beaten in place at one time after being shortened, the on-site lengthening welding is not needed, the construction cost is effectively reduced, the construction period is shortened, and the quality safety risk is reduced.

Description

Steel sheet pile cofferdam structure of deep silt geology closes on structure

Technical Field

The utility model relates to the field of bridge construction, in particular to a steel sheet pile cofferdam structure of a deep silt geological proximity structure.

Background

In recent years, the expressway and the railway in China are rapidly developed, and bridges are adopted to span when meeting special terrains such as rivers, lakes and the like. Thicker covering layers exist at bridge pier positions of most of plains, beaches, seaports, rivers and the like, bearing platforms are buried under the ground deeply, and slope-releasing excavation and steel sheet pile cofferdam support excavation methods can be adopted for construction according to actual geological conditions during construction of the bearing platforms.

For the positions of alluvial plains, coastal zones and the like, the thickness of a sludge layer generally exceeds 20m, when steel sheet pile cofferdams are adopted for construction, the designed inserting and beating depth of the steel sheet piles generally exceeds 20m and even reaches more than 30m, and the overlong steel sheet piles cannot be directly transported by roads due to large length, so that the overlong steel sheet piles need to be transported to the site in sections and then inserted and beaten after being lengthened by welding at the construction site, the lengthening workload of the steel sheet piles is large, the construction cost is high, and the welding quality is difficult to guarantee due to the influence of supporting facilities on the site.

In addition, for the excavation construction of the foundation pit close to the position of the structure with the extremely large weight, the silt at the base of the cofferdam is easy to slide under the action of the gravity of the close structure to cause the base to bulge and further cause the instability of the cofferdam, so effective measures are needed to be taken to ensure that the structure and the soil body beside the foundation pit subside and horizontally displace during the construction of the foundation pit, and the soil body after the foundation pit is backfilled is not subsided and displaced to ensure the safety of the structure.

SUMMERY OF THE UTILITY MODEL

Aiming at the defects in the prior art, the utility model aims to provide a steel sheet pile cofferdam structure of a deep sludge geological adjacent structure and a construction method thereof, wherein cement mixing piles are fully utilized to pertinently reinforce the bottom of a foundation pit, the length of a steel sheet pile is reduced to be within the whole transport range, medium coarse sand is adopted for backfilling and vibrating compaction is carried out on the side close to a large embankment, and the problem that the structure is settled and displaced or even damaged due to the fact that the backfilling material is not compacted during the construction period of the cofferdam adjacent structure or after the backfilling under the deep sludge geological condition is solved.

The utility model is realized by the following technical scheme:

a steel sheet pile cofferdam structure of a deep silt geological proximity structure comprises steel sheet piles, surrounding purlins, steel pipe inclined struts, steel pipe counter struts, cement mixing piles and concrete cushion layers; the steel sheet pile is used as a structure for resisting the pressure of a soil body and stopping water; the purlin, the steel pipe diagonal brace and the steel pipe diagonal brace are connected into a whole by welding and serve as an inner supporting force structure to bear the horizontal thrust transmitted by the steel sheet pile; the cement mixing pile is arranged inside the enclosing purlin and used for pre-treating soil below a reinforcing base in advance; the concrete cushion layer is arranged at the upper end of the cement mixing pile, is used as a base construction working platform and participates in partial stress.

Further, the steel pipe diagonal brace is welded on the adjacent edge of the purlin in an inclined mode.

Further, the steel pipe is to propping vertical welding in enclosing purlin's the edge of subtending.

Further, the construction method of the steel sheet pile cofferdam of the deep sludge geology adjacent structure is used for two bearing platforms constructed on the bored pile, the two bearing platforms are arranged in a parallel and staggered mode, the bearing platforms are adjacent to a dam, the deep sludge geology is within the range of the bearing platforms and the range below the bearing platforms, and the construction method comprises the following steps:

s1, after the construction of the bridge pile foundation is completed, reinforcing sludge in a range below the bottom of the foundation pit within the inner side range of the design position of the steel sheet pile by using the cement mixing pile;

s2, synchronously inserting and driving steel sheet piles by using a steel sheet pile inserting and driving manipulator while reinforcing sludge below the bottom of the foundation pit by using the cement mixing pile;

step S3, excavating a foundation pit by using an excavator to 50cm below the bottom of a bracket, mounting the bracket, and then mounting an enclosing purlin and a steel pipe diagonal brace in the cofferdam on the bracket;

step S4, continuously excavating to the bottom of the foundation pit, cleaning and leveling, pouring a concrete cushion layer and a construction bearing platform, and then dismantling the steel pipe which is superposed with the pier body position and constructing the pier body after oppositely supporting;

step S5, after the pier body construction is completed, backfilling the foundation pit by adopting medium coarse sand and common soil; and then sequentially removing the residual steel pipe diagonal braces, the enclosing purlins and the brackets, and finally pulling out the steel sheet piles.

Further, the cement mixing piles are used for carrying out encryption and reinforcement on the steel plate piles to the outermost row of pile foundations according to the constructed subsection condition of the bridge pile foundations, and the pile foundations are reinforced according to the common interval; the treatment depth, the treatment range and the cement mixing pile spacing are adjusted according to requirements.

Furthermore, the left and right panels are supported by an integral cofferdam, the single-panel purlin, the steel pipe diagonal brace and the steel pipe diagonal brace are connected into a whole by welding, and the left and right panels are symmetrically arranged.

Furthermore, in the construction of foundation pit backfilling, a gap between a bearing platform close to the structure side and the steel plate pile is backfilled by using medium coarse sand with good stress performance, and the medium coarse sand is saturated by water irrigation and is compacted by using a vibrating rod; and the gaps between the other side bearing platforms and the steel plate pile are backfilled by common soil.

Further, in step S3, before excavation, monitoring points are respectively set on the steel sheet pile outer ground and the structure, and settlement and displacement monitoring measurement is performed on the steel sheet pile outer ground and the structure through the observation points during construction.

Furthermore, the monitoring points are concrete blocks, a reinforcing steel bar with a cross-shaped central scribed line is arranged in the middle of each concrete block, and the monitoring points are buried below the ground.

The utility model has the beneficial effects that:

the utility model adopts the cement mixing pile to reinforce the sludge in a certain range below the foundation, reduces the disturbance of foundation pit construction to the levee and the structures beside, increases the anti-uplift performance of the flow-plastic sludge foundation and effectively shortens the length of the steel plate pile. The construction method can realize rapid construction, shorten construction period and reduce quality safety risk. Compared with the conventional steel sheet pile cofferdam method, the length of the steel sheet pile adopted by the method is reduced by more than 30%, so that the steel sheet pile is transported and driven in a whole section, the workload of lengthening and welding a large number of steel sheet piles is reduced, the investment of material equipment is reduced, the method is energy-saving and environment-friendly, and meanwhile, the operation environment of construction operators is effectively improved.

Drawings

FIG. 1 is a schematic elevation view of an embodiment of the present invention;

FIG. 2 is a cross-sectional view taken along line I-I of FIG. 1;

FIG. 3 is a sectional view taken along line II-II of FIG. 1;

FIG. 4 is a diagram of the internal support structure;

FIG. 5 is a schematic view of the synchronous construction of the internal cement mixing pile and the steel sheet pile by inserting and driving;

FIG. 6 is a schematic illustration of the inner support in the inner first layer as installed;

FIG. 7 is a schematic view of the pier body after construction and before backfilling;

FIG. 8 is a schematic diagram of the bearing platform and the steel plate pile after backfilling;

fig. 9 is a schematic drawing of the steel sheet pile after the inner support is removed.

In the drawings: 1-steel sheet pile; 2-enclosing purlin; 31-steel pipe diagonal bracing; 32-steel pipe opposite bracing; 4-bracket; 5-cement mixing pile; 6-concrete cushion; 7-medium coarse sand; 8-ordinary soil; 9-the completed bored pile; 10-a cushion cap; 11-pier body; 12-a monitoring point; 13-inserting and driving a mechanical arm for the steel sheet pile; 14-cement mixing pile machine.

Detailed Description

The utility model will be described in detail with reference to the drawings and specific embodiments, which are illustrative of the utility model and are not to be construed as limiting the utility model.

It should be noted that all the directional indications (such as up, down, left, right, front, back, upper end, lower end, top, bottom … …) in the embodiments of the present invention are only used to explain the relative position relationship between the components, the movement situation, etc. in a specific posture (as shown in the drawings), and if the specific posture is changed, the directional indication is changed accordingly.

In the present invention, unless expressly stated or limited otherwise, the term "coupled" is to be interpreted broadly, e.g., "coupled" may be fixedly coupled, detachably coupled, or integrally formed; can be mechanically or electrically connected; they may be directly connected or indirectly connected through intervening media, or they may be connected internally or in any other suitable relationship, unless expressly stated otherwise. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In addition, the descriptions related to "first", "second", etc. in the present invention are only for descriptive purposes and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one such feature; in addition, technical solutions between various embodiments may be combined with each other, but must be realized by a person skilled in the art, and when the technical solutions are contradictory or cannot be realized, such a combination should not be considered to exist, and is not within the protection scope of the present invention.

Referring to fig. 1-4, the steel sheet pile cofferdam structure of the deep silt geological adjacent structure comprises a steel sheet pile 1, an enclosing purlin 2, a steel pipe diagonal brace 31, a steel pipe diagonal brace 32, a cement mixing pile 5 and a concrete cushion 6; the steel sheet pile 1 is used as a structure for resisting the pressure of a soil body and stopping water; the enclosing purlin 2, the steel pipe diagonal brace 31 and the steel pipe diagonal brace 32 are connected into a whole through welding and used as an inner supporting force structure to bear the horizontal thrust transmitted by the steel sheet pile 1; the cement mixing pile 5 is arranged inside the surrounding purlin 2 and used as soil mass below a pre-treated reinforcing base in advance; the concrete cushion 6 is arranged at the upper end of the cement mixing pile 5, serves as a base construction working platform and participates in partial stress.

Specifically, in this embodiment, the steel pipe diagonal brace 31 is welded to the adjacent edge of the purlin 2 in an inclined manner.

Specifically, in this embodiment, the steel pipe counter stays 32 are vertically welded to opposite sides of the purlin 2.

Referring to fig. 1 to 4, an embodiment of the utility model provides a steel sheet pile cofferdam construction method for a deep-sludge geological adjacent structure, which is used for two parallel bearing platforms arranged in a staggered manner, wherein the bearing platforms are adjacent to a dam or other structures, and deep-sludge geology is arranged in the range of and below the bearing platforms. The cofferdam used in the method has the main stress structure of a steel sheet pile 1, an enclosing purlin 2, a steel pipe inclined strut 31, a steel pipe counter strut 32, a cement mixing pile 5 and a concrete cushion 6. The steel sheet pile 1 is used as a structure for resisting soil pressure and stopping water, and the steel sheet pile is a full-length steel sheet pile without sectional lengthening; the enclosing purlin 2, the steel pipe diagonal brace 31 and the steel pipe diagonal brace 32 are connected into a whole by welding and used as an inner support stressed structure to bear horizontal thrust transmitted by the steel sheet pile; the cement mixing pile 5 is used for pre-treating and reinforcing soil mass in a certain range below the substrate in advance, so that the anti-uplift performance of the soil mass is improved, and the stability of the substrate is ensured; the concrete cushion 6 serves as a foundation construction working platform and participates in partial stress.

As shown in fig. 5, after the construction of the cast-in-situ bored pile 9 at the pier position is completed, firstly, the plane positions of the steel sheet pile 1 and the cement mixing pile 5 are measured and lofted; carrying out foundation reinforcement treatment construction by adopting a cement mixing pile machine 14, wherein foundation reinforcement is divided into an encryption treatment area and a conventional treatment area according to design; when the cement mixing pile 5 is constructed, the steel sheet pile inserting and beating mechanical arm 13 is adopted to synchronously carry out the inserting and beating construction of the steel sheet pile 1 one by one so as to save the construction period.

As shown in fig. 6, after excavating a foundation pit by using an excavator until the height of the foundation pit is 0.5m below the corbels 4, welding the corbels 4 on the steel sheet piles 1 according to the designed quantity and positions, wherein full welding is needed, and the height of a welding line meets the requirements of a drawing; purlin 2 is enclosed in the installation on bracket 4, encloses the complete installation of purlin 2 and accomplishes the back, and installation steel pipe bracing and steel pipe are to propping, and steel pipe bracing and steel pipe all adopt the steel pipe to propping the mid portion, and the end sets up the steel wedge, and the voussoir both ends enclose purlin welded connection with steel pipe, shaped steel respectively.

As shown in fig. 7, the excavation of the foundation pit is continued by using an excavator until the elevation of the bottom of the foundation pit concrete cushion 6 is reached, then the foundation is cleaned and leveled, and the concrete cushion is poured; and constructing a bearing platform 10 after the cushion layer meets the strength, and dismantling the steel pipe counter-support colliding with the pier body 11 after the construction of the bearing platform is finished to finish the construction of the pier body 11.

As shown in figure 8, the gaps between the bearing platform and the steel plate pile are backfilled to be flush with the top of the bearing platform, wherein the side close to the structure is backfilled in a layered mode by using medium coarse sand 7, the filling water in the layered mode is saturated, then the filling water is vibrated by using a vibrating rod to be compact, and the gaps between the other sides and the two bearing platforms are backfilled by using common soil 8.

As shown in fig. 9, the steel pipe diagonal brace is removed, then the surrounding purlin 2 is removed, then the bracket 4 is removed, the foundation pit is backfilled to the same elevation as the original ground, and the steel sheet pile 1 is completely pulled out by the steel sheet pile inserting and driving mechanical arm 13.

As shown in fig. 1 and 5-8, before cofferdam excavation, a certain number of monitoring points 12 are pre-buried in advance on the outer side of a structure and a steel sheet pile 1, initial data is measured before excavation, the monitoring points 12 are regularly measured during the period from excavation of a foundation pit to backfilling of the foundation pit to pulling out of the steel sheet pile, the measurement result is compared with the initial data, whether horizontal displacement and settlement displacement generated on the ground beside the structure and the foundation pit exceed a standard and a design allowable value or not is rechecked, and if the horizontal displacement and the settlement displacement exceed the standard and the design allowable value, operation is immediately stopped until construction can be continued after danger is eliminated.

According to the construction method provided by the embodiment of the utility model, the bearing platform with deep sludge at the pier position and a structure with extremely large near weight is constructed by adopting a steel sheet pile cofferdam method, and after the range below the bottom of the cofferdam foundation pit is reinforced by the cement mixing pile, the length of the steel sheet pile is greatly reduced to the range of whole-section transportation and whole-section hoisting and inserting. The foundation reinforcement and the inserting and driving of the steel sheet piles are carried out synchronously, and the construction period is effectively shortened. And medium coarse sand is adopted for backfilling at the side close to the structure, and water is filled for saturation and vibration compaction, so that the backfilled soil is prevented from being compressed and sliding due to the extrusion of the structure after the steel sheet pile is pulled out. The utility model solves the problems of large length of the steel sheet pile under deep silt geology, large joint field lengthening welding amount and difficult quality guarantee, and also solves the problems of large foundation pit uplift and cofferdam structure deformation instability risk under the condition that the bearing platform is close to a structure with extremely large weight.

The technical solutions provided by the embodiments of the present invention are described in detail above, and the principles and embodiments of the present invention are explained herein by using specific examples, and the descriptions of the embodiments are only used to help understanding the principles of the embodiments of the present invention; meanwhile, for a person skilled in the art, according to the embodiments of the present invention, there may be variations in the specific implementation manners and application ranges, and in summary, the content of the present description should not be construed as a limitation to the present invention.

Claims (3)

1. The utility model provides a steel sheet pile cofferdam structure of structure is close to deep silt geology which characterized in that: the concrete filling pile comprises a steel sheet pile, a surrounding purlin, a steel pipe inclined strut, a steel pipe opposite strut, a cement mixing pile and a concrete cushion layer; the steel sheet pile is used as a structure for resisting the pressure of a soil body and stopping water; the purlin, the steel pipe diagonal brace and the steel pipe diagonal brace are connected into a whole by welding and serve as an inner supporting force structure to bear the horizontal thrust transmitted by the steel sheet pile; the cement mixing pile is arranged inside the enclosing purlin and used for pre-treating soil below a reinforcing base in advance; the concrete cushion layer is arranged at the upper end of the cement mixing pile, is used as a base construction working platform and participates in partial stress.

2. The steel sheet pile cofferdam structure of deep silt geological adjacent structure of claim 1, characterized in that: the steel pipe diagonal brace is welded on the adjacent edge of the surrounding purlin in an inclined mode.

3. The steel sheet pile cofferdam structure of deep silt geological adjacent structure of claim 1, characterized in that: the steel pipe is to propping vertical welding in enclose purlin to the edge.

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