CN211898526U - Pile foundation underpinning protection device based on limited space - Google Patents

Abstract

The invention discloses a pile foundation underpinning protection device based on a limited space, which comprises a pile foundation temporary protection steel bracket, a steel beam and a jack, wherein the steel beam is arranged on the pile foundation temporary protection steel bracket; the steel bracket is used for bearing the vertical stress of the bridge and comprises two steel beams; the steel beam is transversely arranged on the two steel brackets and adopts a prestressed structure; the jack is arranged at the end of the underpinning pile, and the protection of pile foundation underpinning construction is realized by jacking the steel beam in advance. The equipment can be used in a limited space and can be dismantled after being used up.

Description

Pile foundation underpinning protection device based on limited space

Technical Field

The utility model belongs to the rail transit field specifically says, relates to overpass pile foundation underpinning device under the limited space operating mode.

Background

The subway is one of the most main forms of underground traffic, and the construction space of the subway has the characteristics of narrow space, high construction difficulty, high resource and energy consumption, high pollution to urban environment and the like. Therefore, the method has very important practical significance for improving the speed and the quality of underground space construction and protecting the underground environment. The restricted space import and export is restricted, leads to the ventilation scheduling problem easily, and the phenomenon that inflammable and explosive, harmful and toxic material pile up and the oxygen deficiency can exist takes place, and subway construction space is as typical restricted space, and it is crucial to guarantee personnel's safety in the work progress.

The pile foundation underpins through newly-built pile foundation and underpinning the structure, effectively transfers the upper portion load that existing pile foundation bore to newly-built pile foundation and underpinning the structure, and in the construction implementation of underground works, the subway line position takes place sometimes with the condition that the bridge pile foundation of the current operation conflicts, and pile foundation underpinning technique is one of the processing scheme of solving this kind of engineering problem.

Disclosure of Invention

The problem to current finite space construction, the utility model provides an overpass pile foundation underpins protection device for restricted space, this application device can provide the protection when carrying out the pile foundation underpins to the overpass pier in the finite space for guarantee construction when carrying out the pile foundation underpins is stable goes on, protects constructor's safety simultaneously.

In order to achieve the above object, the present invention provides the following solutions: the pile foundation underpinning protection device based on the limited space comprises a steel bracket, a steel beam and a jack; the pile foundation underpinning protection device comprises a steel support, a steel pile foundation underpinning protection device and a steel pile foundation underpinning protection device, wherein the steel support is mainly used for temporarily replacing an old pile foundation when the old pile is dismantled; the steel beam is transversely arranged on the two steel supports and adopts a prestressed structure for realizing the support of the bridge. The jack is provided with and underpins the pile end, the protection of the pile foundation underpinning construction is realized by jacking the steel beam in advance, and the specific structural diagram of the protection device is shown as the attached drawing 1.

The steel support is mainly used for bearing vertical stress, the main materials are Q235-B type steel bars and HPB 300-grade steel bars, and the main welding mode is arc welding. The steel bar connector adopts a rolled straight thread steel bar connector, the ratio of the measured tensile strength value to the measured yield strength value of the steel bar should not be less than 1.20, and the ratio of the measured yield strength value to the standard strength value of the steel bar should not be more than 1.3. The steel should have a significant yield step and elongation greater than 20%. The steel should have good weldability and acceptable impact toughness. The measured values of the total elongation of the HPB 300-grade and HRB 400-grade steel bars under the maximum tension are not less than 10% and 9%.

The steel beam is mainly used for temporarily bearing the bridge, plays a role in temporarily supporting the bridge in the process of removing the old pile to replace the new pile, and is removed together with the steel support after the new pile is completely supported and stably stressed.

The jack is mainly used for underpinning loading, the underpinning loading mode is graded loading, the safety device is locked after the graded loading is carried out to the designed jacking force, and the cushion block is placed.

The utility model has the advantages of as follows: the steel bracket and the steel beam are simple in arrangement, strong in operability and simple and convenient to maintain, and can be reasonably placed according to different occasions; the equipment can be used in a limited space, can be dismantled after use, and has the advantages of small occupied space, convenience in dismantling, no influence on subsequent construction and the like.

Drawings

Fig. 1 is a schematic view of the present invention.

Fig. 2 is a schematic view of jack installation.

Reference numerals: 1-existing bridge, 2-jack, 3-steel beam, 4-existing bridge pier, 5-steel support, 6-underpinning crossbeam, 7-existing bearing platform, 8-existing pile foundation, 9-ground connecting wall, and 10, 11-underpinning pile.

Detailed Description

The present invention will be further described in detail with reference to the accompanying drawings.

The utility model comprises a pile foundation temporary protection steel bracket 5, a steel beam 3 and a jack 2; the steel bracket 5 is used for bearing the vertical stress of a bridge 5 and comprises two steel beams 3; the steel beam 3 is transversely arranged on the two steel brackets and adopts a prestressed structure; the jack 2 is arranged at the end of the underpinning pile, and the protection of pile foundation underpinning construction is realized by jacking the steel beam 3 in advance. The steel beam 3 is symmetrically arranged on the bridge pier. The jack 2 is used for underpinning and loading in a grading mode, and the jack is provided with a self-locking device. Fig. 1 is a schematic view of the present invention.

Fig. 2 is a schematic view of jack installation.

The specific embodiment is as follows:

the pile foundation underpinning protection device is applied to a standard-section drum tower intersection station 04 on the first-stage project of track traffic No. 1 of Haohote city, and construction is smoothly completed. The drum-tower interchange C-turn road bridge is positioned at the southeast side of the three-layer interchange drum-tower interchange, is a turning communicating bridge for turning the east-west main bridge to the north-south main bridge, the line bridge is a continuous beam bridge, the width of the bridge floor is 8m, the span is 18-22m, the underpinned bridge pier is No. 1 bridge pier, the size is 1.1-1.1 m, the size of the bearing platform is 5.2-2.2-1.5 m (length, width, height), two bored cast-in-place piles with the diameter of 1.2m and the length of 25m are arranged below the bridge pier, and the two barrier piles are positioned in the outline of the main body of the station, so that the normal construction of the subway is hindered, and the normal construction of the main body of the station can be ensured only after the barrier piles are removed in advance. The pile foundation underpinning project is provided with 4 drilled piles with the pile diameter of 1.4m and the length of 40m, and the steel beams are prestressed concrete beams with the width of 6.65m, the height of 2.8m and the length of 27.3 m.

The active pile foundation underpinning method comprises the following specific steps: the method comprises the steps of arranging a steel support to support the upper bridge floor of No. 1 pier, constructing underpinning piles, excavating foundation pits at an existing bearing platform, chiseling and embedding ribs on the existing bearing platform, wrapping the existing bearing platform, pouring underpinning girders and a first pouring section, stretching the prestressed force of the underpinning girders, jacking the underpinning girders through jacks placed at the pile tops of the underpinning piles, cutting off old piles, removing the steel support, pouring a later section, coordinating the construction of the main foundation pits, and finishing underpinning.

At the in-process that the pile foundation underpins, must at first protect the atress balance of existing bridge with an interim support, consequently this pile foundation underpins protection device can play the guard action to the bridge, because the bridge below space is narrow and small, adopts conventional mode to be difficult to reach the purpose, consequently the utility model provides an adopt interim steel support to hold up the girder steel to realize the interim protection to the bridge with the hierarchical loaded mode of jack.

In practical application the utility model discloses the time, corresponding material should reach certain standard, and its use is also followed the flow side of regulation and can be realized its complete function, consequently, the utility model provides a need the place of noticing in the use as follows:

(1) the steel support and the girder steel are taken down with the bridge floor, and suitable position community jack (model YSD5001) is selected to girder steel support bridge floor department, and each side respectively places two to the effect that great settlement or slope appear in the bridge roof beam in playing the protection construction, No. 1 pier symmetrical arrangement should be followed to the girder steel, and the jack should also be followed the bridge floor and worn to place more. The bearing capacity of the steel support is designed to be the bridge load borne by No. 1 bridge piers. Before the support is erected, the ground near the support needs to be hardened and pressurized, a miscellaneous fill layer near the steel frame support ground is dug out, the compaction coefficient is 0.95, and a concrete pavement slab with the thickness of 300mm is paved; every side of girder steel respectively places 3 pairs, and the support adopts full hall support, all the other common member of scaffold frame that can adopt, actual utility model discloses the time can be selected by oneself according to particular case, on the girder steel should weld and the steel support, welding length and way should satisfy relevant standard's requirement.

(2) The main materials of the steel support are Q235-B type steel bars and HPB 300-grade steel bars, the main welding mode is arc welding, E43 series welding rods are adopted when the Q235 steel bars and the HPB 300-grade steel bars are welded, and E50 series welding rods are adopted when HRB400 steel bars are welded. The steel bar connector adopts a rolled straight thread steel bar connector, the mechanical property grade is one grade, the ratio of the measured tensile strength value to the measured yield strength value of the steel bar is not less than 1.20, and the ratio of the measured yield strength value to the standard strength value of the steel bar is not more than 1.3. The steel should have a significant yield step and elongation greater than 20%. The steel should have good weldability and acceptable impact toughness. The measured values of the total elongation of the HPB 300-grade and HRB 400-grade steel bars under the maximum tension are not less than 10% and 9%.

(3) The underpinning loading adopts graded loading, the total load is 12 grades, the load increment of each grade is 10 percent of the designed jacking force of the jack, and the load is held until the new pile is settled and stabilized, and then the load is unloaded to 100 percent in grades according to 0.1 mm/h; and each stage of loading needs to be carried out for 20 minutes, a secondary load can be loaded behind the stable structure of the knot, the secondary load is loaded to the designed jacking force in a grading manner, the safety self-locking device is locked, the cushion block is placed, and the safety self-locking device of the jack needs to be locked in each stage of loading and unloading processes. The jacking forces of the respective stages are shown in Table 1

TABLE 1 lifting force of jack at all levels

At the in-process of underpinning, need carry out pier department jacking displacement and jacking force two accuse, the jacking displacement is as main control factor, the utility model provides a jacking force only supplies the reference, requires the loading process slow during the construction, strengthens monitoring frequency to monitoring data carries out the jacking for guiding.

During jacking, each pile top is provided with two YSD500 jacks and two solid steel pipe columns, the sectional area of each steel column is not less than 0.05 square meter, the specific placement position can refer to the attached figure 2, the positions of the pile top and the underpinning bottom beam relative to the jacks and the steel columns are provided with embedded steel cushion blocks, and the thickness of each steel cushion block is 20 mm; 4 jacks on the left side and the right side of the underpinning are controlled by an oil pump respectively and synchronously jacked. The combined centroid of the jack without a replacement pile must coincide with the centroid of the underpinned pile.

Claims (3)

1. The utility model provides a pile foundation underpins protection device based on confined space which characterized in that: the temporary protection steel support comprises a pile foundation temporary protection steel support, a steel beam and a jack;

the steel bracket is used for bearing the vertical stress of the bridge and comprises two steel beams;

the steel beam is transversely arranged on the two steel brackets and adopts a prestressed structure;

the jack is arranged at the end of the underpinning pile, and the protection of pile foundation underpinning construction is realized by jacking the steel beam in advance.

2. The confined space-based pile foundation underpin protection device of claim 1, wherein: the steel beam piers are symmetrically arranged.

3. The confined space-based pile foundation underpin protection device of claim 1, wherein: the jack underpinning loading adopts the step loading, and the jack is provided with a self-locking device.

Images