Adjustable steel support structure and erection method for semi-covered subway station foundation pit

Abstract

The present invention provides an adjustable steel support structure and a construction method for erecting a semi-covered subway station foundation pit, wherein the steel support structure comprises an active end, two adjustable sections, an intermediate section and a fixed end, wherein the active end, one adjustable section, the intermediate section, another adjustable section and the fixed end are connected in sequence; the intermediate section comprises a connecting pipe fixed section and multiple non-connecting pipe fixed sections, the non-connecting pipe fixed sections are connected to the two ends of the connecting pipe fixed section, and the connecting pipe fixed section and the non-connecting pipe fixed section are connected to form an intermediate section; the two adjustable sections are connected through a horizontal connecting pipe, the interior of the adjustable section is hollow and filled with liquid, and the liquid in one adjustable section can enter the other adjustable section through the horizontal connecting pipe. The steel support structure and the construction method for erecting the steel support structure can adjust the horizontal inclination angle of the steel support structure in real time during the process of hoisting and erecting, and the gravity of the steel support structure on both sides of the lifting point is adjusted by liquid, which greatly reduces the risk of the hoisting process.

Description

Technical Field

[0001] The invention relates to the field of steel support erection for a semi-covered excavation foundation pit, and in particular to an adjustable steel support structure for a semi-covered excavation subway station foundation pit and an erection construction method. Background Art

[0002] At present, the mainstream construction methods of subway stations include open-cut method, semi-covered excavation method and covered excavation method. Semi-covered excavation method, as a construction method that combines open-cut and covered excavation, is characterized by the clever laying of longitudinal local road surface covered excavation system according to road traffic needs, and the rest is used as a transportation channel for open-cut construction, excavating the foundation pit from top to bottom, and then constructing the main structure from bottom to top. The use of this model not only effectively expands the construction site space and alleviates the problem of tight construction land in urban areas, but also ensures the rapid excavation of the foundation pit and the realization of construction functions.

[0003] In the construction of deep foundation pits of subway stations, the combined support system of retaining piles (walls) and internal supports is widely used. In particular, steel supports, due to their many advantages such as recyclable materials, short construction period, and convenient prestressing, occupy an important position in the deep foundation pit support structure of urban subway stations. The erection of steel supports is a key link to ensure the stability of the foundation pit of subway stations. Reliable, safe and convenient installation technology can ensure the timeliness of foundation pit support operations and play a vital role in controlling foundation pit deformation. The untimely erection of steel supports is one of the key factors that lead to excessive deformation of the foundation pit and even instability and damage. When the open-cut method is used for construction, the construction space is spacious and heavy machinery and equipment can be used to directly carry out the lifting construction of steel supports. However, in the construction environment of the semi-cover excavation method, due to the limited working space, it is usually necessary to use lifting equipment outside the foundation pit to transport the assembled steel supports to the installation location, and then use excavators, winches, hand winches, electric winches and other equipment and manual cooperation to complete the installation. Due to the lack of unified steel support installation operation procedures, this method still has certain construction safety risks.

[0004] At present, there are problems in the deep foundation pit support project of semi-excavated railway stations, such as difficulty in lifting and erecting steel supports, high safety risks in lifting and erection, poor controllability of lifting, low erection efficiency, and difficulty in real-time control of erection angles.

[0005] In view of the above reasons, there is a need for an adjustable steel support structure and an erection construction method for a semi-covered subway station foundation pit. Summary of the invention

[0006] The purpose of the present invention is to provide an adjustable steel support structure and an erection construction method for a semi-covered subway station foundation pit, which can accurately adjust the erection angle of the steel support during the erection of the steel support structure, thereby improving the efficiency and safety of the steel support hoisting and erection in the semi-covered deep foundation pit project, and providing a strong guarantee for the construction safety and quality improvement of the subway station.

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] A semi-excavated subway station foundation pit adjustable steel support structure, the steel support structure comprises an active end, two adjustable sections, an intermediate section and a fixed end, wherein the active end, one adjustable section, the intermediate section, another adjustable section and the fixed end are connected in sequence; the intermediate section comprises a connecting pipe fixed section and multiple non-connecting pipe fixed sections, the non-connecting pipe fixed sections are connected to both ends of the connecting pipe fixed section, the connecting pipe fixed section and the non-connecting pipe fixed section are connected to form the intermediate section; the two adjustable sections are connected by a horizontal connecting pipe, the interior of the adjustable section is hollow and filled with liquid, and the liquid in one adjustable section can enter the other adjustable section through the horizontal connecting pipe.

[0009] Furthermore, in the above-mentioned adjustable steel support structure of the semi-excavated subway station foundation pit, the adjustable section close to the flexible end is an adjustable end adjustable section, and the adjustable section close to the fixed end is a fixed end adjustable section; the flexible end and the flexible end adjustable section, the flexible end adjustable section and the intermediate section, the intermediate section and the fixed end adjustable section, the fixed end adjustable section and the fixed end, and the connecting pipe fixed section and the non-connecting pipe fixed section are all connected by flanges and bolts; the number of the non-connecting pipe fixed sections on both sides of the connecting pipe fixed section is the same; an axial force gauge is provided on the fixed end; the material of the horizontal connecting pipe is PVC pipe or PPR pipe.

[0010] Furthermore, in the above-mentioned semi-covered subway station foundation pit adjustable steel support structure, the upper side wall of the active end adjustable section, the upper side wall of the connecting pipe fixed section, the upper side wall of the fixed end adjustable section and the upper side wall of the non-connecting pipe fixed section are all provided with lifting points, and the three adjacent lifting points are used as lifting points for the crane to lift the steel support structure, and the three lifting points are respectively the main lifting point in the middle and the left auxiliary lifting point and the right auxiliary lifting point on both sides; the horizontal distance between the left auxiliary lifting point and the main lifting point is d 1. The horizontal distance between the right auxiliary suspension point and the main suspension point is d 2. A main lifting rope is provided on the main lifting point, and the length of the main lifting rope is H 1. The left auxiliary lifting point is provided with a left auxiliary lifting rope, and the length of the left auxiliary lifting rope isH 2. The right auxiliary lifting point is provided with a right auxiliary lifting rope, and the length of the right auxiliary lifting rope is H 3. By adjusting the length of the left auxiliary lifting rope or the right auxiliary lifting rope, the steel support structure can be hoisted into the foundation pit in an inclined state; when the steel support structure is in a horizontal state, only the main lifting rope is subjected to force, and the left auxiliary lifting rope and the right auxiliary lifting rope are both in a relaxed state; when one side of the active end is tilted downward for hoisting, the three lifting points are all set on the side close to the fixed end, the left auxiliary lifting rope plays a role of auxiliary hoisting, and the right auxiliary lifting rope plays a role of limiting vertical displacement to prevent the reverse tilt angle of the fixed end side of the steel support structure from being too large during the horizontal regulation process. At this time, the length of the left auxiliary lifting rope H 2 is:

[0011] Formula (1)

[0012] In formula (1), H 1 is the length of the main suspension rope; d 1 is the horizontal distance between the left auxiliary suspension point and the main suspension point; α It is the angle between the axis of the steel support structure and the horizontal plane during tilted lifting;

[0013] The length of the right auxiliary lifting rope H 3 is:

[0014] Formula (2)

[0015] In formula (2), H 1 is the length of the main suspension rope; d 2 is the horizontal distance between the right auxiliary suspension point and the main suspension point; ε is the vertical displacement limit value, ;

[0016] When one side of the fixed end is tilted downward for hoisting, the three lifting points are all set on the side close to the flexible end, the right auxiliary lifting rope plays the role of auxiliary lifting, and the left auxiliary lifting rope plays the role of limiting the vertical displacement to prevent the reverse tilt angle of the flexible end side of the steel support structure from being too large during the horizontal adjustment process; at this time, the length of the right auxiliary lifting rope H 3 is:

[0017] Formula (3)

[0018] In formula (3), H 1 is the length of the main suspension rope; d 2 is the horizontal distance between the right auxiliary suspension point and the main suspension point; αIt is the angle between the axis of the steel support structure and the horizontal plane during tilted lifting;

[0019] The length of the left auxiliary lifting rope H 2 is:

[0020] Formula (4)

[0021] In formula (4), H 1 is the length of the main suspension rope; d 1 is the horizontal distance between the left auxiliary suspension point and the main suspension point; ε is the vertical displacement limit value, .

[0022] Furthermore, in the above-mentioned adjustable steel support structure of the semi-excavated subway station foundation pit, a first adjusting pipe opening is provided on the upper side wall of the middle part of the fixed-end regulating section, through which liquid can be injected into the interior of the fixed-end regulating section, and outside air can enter the fixed-end regulating section through the first adjusting pipe opening; a first electrically-controlled valve is provided on the first adjusting pipe opening; a first drainage pipe opening and a first connecting pipe opening are provided on the lower side wall of the middle part of the fixed-end regulating section, and a first manual valve is provided on the first drainage pipe opening, and the first manual valve can be opened to discharge the liquid inside the fixed-end regulating section using the first drainage pipe opening, and one end of the horizontal connecting pipe is connected to the first connecting pipe opening.

[0023] Furthermore, in the above-mentioned adjustable steel support structure of the semi-excavated subway station foundation pit, a second adjusting pipe opening is provided on the upper side wall of the middle part of the active-end regulating section, through which liquid can be injected into the interior of the active-end regulating section, and outside air can enter the active-end regulating section through the second adjusting pipe opening; a second electrically-controlled valve is provided on the second adjusting pipe opening; a second drainage pipe opening and a second connecting pipe opening are provided on the lower side wall of the middle part of the active-end regulating section, and a second manual valve is provided on the second drainage pipe opening, and the second manual valve can be opened to discharge the liquid inside the active-end regulating section using the second drainage pipe opening, and the other end of the horizontal connecting pipe is connected to the second connecting pipe opening.

[0024] Furthermore, in the above-mentioned adjustable steel support structure of the semi-excavated subway station foundation pit, a fixing buckle is provided on the lower side wall of the middle part of the connecting pipe fixing section, and an electrically controlled two-way liquid regulating pump is provided on the horizontal connecting pipe, and the electrically controlled two-way liquid regulating pump is fixed on the fixing buckle; the electrically controlled two-way liquid regulating pump can be used to adjust the liquid in the two regulating sections, thereby fine-tuning the horizontality of the steel support structure.

[0025] Furthermore, in the adjustable steel support structure for the semi-top-down subway station foundation pit described above, a first air extraction port is provided on the upper side wall of the middle part of the fixed-end regulating section, and the first air extraction port is connected to a first air extraction pump through a hose; a second air extraction port is provided on the upper side wall of the middle part of the movable-end regulating section, and the second air extraction port is connected to a second air extraction pump through a hose. By using the first air extraction pump to extract air from the fixed-end regulating section, the liquid in the movable-end regulating section can flow into the fixed-end regulating section through the horizontal connecting pipe. By using the second air extraction pump to extract air from the movable-end regulating section, the liquid in the fixed-end regulating section can flow into the movable-end regulating section through the horizontal connecting pipe. By adjusting the liquid in the fixed-end regulating section and the movable-end regulating section, the level of the steel support structure can be finely adjusted.

[0026] Furthermore, in the adjustable steel support structure for the semi-top-down subway station foundation pit described above, first observation windows are provided on both the front side wall and the rear side wall of the middle part of the fixed-end regulating section, and second observation windows are provided on both the front side wall and the rear side wall of the middle part of the movable-end regulating section; glass is embedded in both the first observation window and the second observation window; the thickness of the glass is A, and the wall thickness of the steel support structure is B, where 3 / 4B < A < B. Scale lines parallel to the axis of the steel support structure are provided on the glass. Through the glass, the internal liquid level conditions of the fixed-end regulating section and the movable-end regulating section can be observed, and the level of the steel support structure can be judged based on the internal liquid level conditions.

[0027] On the other hand, a construction method for erecting the adjustable steel support structure for the semi-top-down subway station foundation pit described above is provided, and the construction method for erection includes the following steps:

[0028] Step 1, determine the hoisting parameters: Determine the inclination angle α of the steel support structure for inclined hoisting into the pit, the positions of the three lifting points, and the length of the main lifting rope according to the cover plate layout of the foundation pit H 1. Calculate the length of the left auxiliary lifting rope through formula (1) or formula (4) H 2. Calculate the length of the right auxiliary lifting rope through formula (2) or formula (3) H 3;

[0029] Step 2, assemble the steel support structure: Assemble the middle section, fixed-end regulating section, movable-end regulating section, fixed end head, and movable end head outside the foundation pit to form the steel support structure;

[0030] Connect the first air extraction pump to the first air extraction port on the fixed-end regulating section through a hose, connect the second air extraction pump to the second air extraction port on the movable-end regulating section through a hose, close the first manual valve and the second manual valve, and weld an axial force gauge on the fixed end head;

[0031] Step 3, tilted hoisting into the pit: Use a crane and adopt a three-point hoisting method with the main hoisting point, the left auxiliary hoisting point and the right auxiliary hoisting point to hoist the steel support structure into the foundation pit in an inclined state;

[0032] Step 4: Liquid injection and leveling: Open the first and second electronically controlled valves, close the electronically controlled two-way liquid adjustment pump, and calculate the liquid injection volume required to restore the steel support structure to a horizontal state based on the position of the main suspension point. V , according to the calculated injection volume V Inject liquid into the control section close to the main suspension point;

[0033] Step 5, fine-tuning the horizontality: open the electrically controlled two-way liquid regulating pump on the fixed section of the connecting pipe, and connect the fixed-end regulating section with the flexible-end regulating section through the horizontal connecting pipe; if one side of the fixed end is to be moved downward, close the first electrically controlled valve on the fixed-end regulating section, open the second electrically controlled valve on the flexible-end regulating section, use the first vacuum pump to pump air, and the liquid in the flexible-end regulating section flows to the fixed-end regulating section; if one side of the flexible end is to be moved downward, close the second electrically controlled valve on the flexible-end regulating section, open the first electrically controlled valve on the fixed-end regulating section, use the second vacuum pump to pump air, and the liquid in the fixed-end regulating section flows to the flexible-end regulating section; observe the scale position of the glass corresponding to the liquid inside the fixed-end regulating section through the first observation window, observe the scale position of the glass corresponding to the liquid inside the flexible-end regulating section through the second observation window, and achieve the purpose of real-time fine-tuning of the horizontality of the steel support structure by adjusting the height of one side of the fixed end or one side of the flexible end;

[0034] Step 6, placing the steel support structure: placing the steel support structure with adjusted levelness on the steel bracket on the purlin;

[0035] Step 7, applying axial force: according to the pre-stressed axial force calibration value of the steel support structure design and construction, a hydraulic jack is used to apply prestress to the steel support;

[0036] Step 8, dismantle the steel support structure: dismantle the steel support structure, inject liquid into the flexible end control joint or the fixed end control joint to make the steel support structure in a tilted state, hoist the steel support structure out of the foundation pit, open the first manual valve on the fixed end control joint to drain the liquid in the fixed end control joint, open the second manual valve on the flexible end control joint to drain the liquid in the flexible end control joint, and dismantle the first vacuum pump and the second vacuum pump.

[0037] Furthermore, in the above-mentioned construction method for erecting an adjustable steel support structure for a semi-covered subway station foundation pit, in step 4, the water injection amount of the fixed end regulating section and the movable end regulating section is calculated according to the on-site construction conditions. Fis the tension at the main suspension point when the steel support structure is in a horizontal state, and is the bending moment at the main suspension point when the steel support structure is in a horizontal state. M = 0, the gravity of the liquid in the fixed end control section and the flexible end control section is approximated as a uniformly distributed load for calculation, and the bending moment at the main suspension point in the horizontal state M The calculation formula is as follows:

[0038] Formula (5)

[0039] In formula (5), q 1 is the unit length gravity of the steel support structure, N; q 2 is the gravity per unit length of the liquid in the fixed end regulating section and the flexible end regulating section, N; G 1 is the gravity difference per unit length between the fixed end or the movable end close to the main suspension point and the steel support structure, N; G 2 is the gravity difference per unit length between the fixed end or the movable end on the side away from the main suspension point and the steel support structure, N; is the length of the steel support structure, m; is the length of the movable end or fixed end close to the main suspension point. is the length of the flexible end regulating section or the fixed end regulating section close to the main suspension point, m; is the horizontal distance from the main suspension point to the active end regulating section or the fixed end regulating section on the side close to the main suspension point, m; d is the differential sign; ; ; By simplifying formula (5), the liquid filling volume of the fixed end control section or the flexible end control section close to the main suspension point can be obtained: V for:

[0040] Formula (6)

[0041] In formula (6), q 1 is the unit length gravity of the steel support structure, N; G 1 is the gravity difference per unit length between the fixed end or the movable end close to the main suspension point and the steel support structure, N; G 2 is the gravity difference per unit length between the fixed end or the movable end on the side away from the main suspension point and the steel support structure, N; is the length of the active end regulating section or the fixed end regulating section, m; The horizontal distance between the active end control section or the fixed end control section and the main suspension point, m; ρ is the liquid density, kg / m 3 .

[0042] Analysis shows that the present invention discloses an adjustable steel support structure and an erection construction method for a semi-covered subway station foundation pit, which can efficiently, safely and accurately complete the erection of steel supports, and can also conveniently dismantle the steel support structure, filling the gap of the lack of an effective, feasible and scientific method for erecting semi-covered steel supports for subway station foundation pits. The erection construction method can adjust the horizontal inclination angle of the steel support structure in real time during the hoisting and erection process, and adjusts the gravity of the steel support structure on both sides of the lifting point by liquid, which greatly reduces the risk of the hoisting process, and effectively solves the outstanding problems of irregular operation, high risk, low efficiency and long erection time when the existing gantry crane and excavator combination hoist the foundation pit steel support, etc. At the same time, it also realizes the real-time regulation of the hoisting inclination angle of the steel support structure during the erection process, which is of great significance to the field of hoisting and erection of steel supports for semi-covered foundation pits of subway stations. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. Among them:

[0044] Figure 1 It is a schematic diagram of the three-dimensional structure of an embodiment of the present invention.

[0045] Figure 2 It is a structural schematic diagram of the steel support structure hoisting according to an embodiment of the present invention;

[0046] Figure 3 It is another three-dimensional structural schematic diagram of an embodiment of the present invention;

[0047] Figure 4 It is a schematic diagram of the three-dimensional structure of the middle section according to one embodiment of the present invention;

[0048] Figure 5 It is a schematic diagram of the three-dimensional structure of a fixed-end regulating section according to an embodiment of the present invention;

[0049] Figure 6 A schematic diagram of the three-dimensional structure of an active end regulating section according to an embodiment of the present invention;

[0050] Figure 7 Another schematic diagram of the three-dimensional structure of the fixed-end regulating section according to an embodiment of the present invention;

[0051] Figure 8 It is another three-dimensional structural schematic diagram of the active end regulating section of one embodiment of the present invention;

[0052] Fig. 9 This is a schematic diagram of the structure of glass according to an embodiment of the present invention;

[0053] Fig.10A balance axis force diagram for calculating the counterweight of a steel support structure according to an embodiment of the present invention;

[0054] Fig.11 A schematic diagram of calculating the length of a suspension rope according to an embodiment of the present invention;

[0055] Fig.12 It is a schematic diagram of the steps of a method for erecting a steel support structure according to an embodiment of the present invention.

[0056] Explanation of the reference numerals: 1 middle section; 2 fixed end regulating section; 3 flexible end regulating section; 4 fixed end; 5 flexible end; 11 connecting pipe fixed section; 12 non-connecting pipe fixed section; 111 fixing buckle; 112 electrically controlled two-way liquid regulating pump; 21 first observation window; 211 glass; 22 first regulating pipe opening; 221 first electrically controlled valve; 23 first air extraction pipe opening; 231 first air extraction pump; 24 first drainage pipe opening; 241 first manual valve; 25 first connecting pipe opening; 251 horizontal connecting pipe; 31 second observation window; 32 second regulating pipe opening; 321 second electrically controlled valve; 33 second air extraction pipe opening; 331 second air extraction pump; 34 second drainage pipe opening; 341 second manual valve; 35 second connecting pipe opening, 61 main hanging point; 62 left auxiliary hanging point; 63 right auxiliary hanging point; 611 main hanging rope; 621 left auxiliary hanging rope; 631 right auxiliary hanging rope. DETAILED DESCRIPTION

[0057] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments. Each example is provided by way of explanation of the present invention and does not limit the present invention. In fact, it will be clear to those skilled in the art that modifications and variations may be made in the present invention without departing from the scope or spirit of the present invention. For example, a feature shown or described as a part of one embodiment may be used in another embodiment to produce yet another embodiment. Therefore, it is desired that the present invention encompasses such modifications and variations within the scope of the appended claims and their equivalents.

[0058] In the description of the present invention, the terms "longitudinal", "lateral", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and do not require that the present invention must be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention. The terms "connected", "connected" and "set" used in the present invention should be understood in a broad sense. For example, it can be a fixed connection or a detachable connection; it can be a direct connection or an indirect connection through an intermediate component; it can be a wired electrical connection, a radio connection, or a wireless communication signal connection. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0059] One or more examples of the present invention are shown in the accompanying drawings. The detailed description uses numbers and letter labels to refer to features in the drawings. Like or similar labels in the drawings and description have been used to refer to like or similar parts of the present invention. As used herein, the terms "first", "second", "third", etc. are used interchangeably to distinguish one component from another and are not intended to indicate the location or importance of individual components.

[0060] like Figures 1 to 12 As shown, according to an embodiment of the present invention, a semi-covered excavation subway station foundation pit adjustable steel support structure is provided, such as Figure 1 As shown, the steel support structure includes an active end 5, two regulating sections, an intermediate section 1 and a fixed end 4, wherein the active end 5, one regulating section, the intermediate section 1, another regulating section and the fixed end 4 are connected in sequence; Figure 4 As shown, the middle section 1 includes a connecting tube fixed section 11 and multiple non-connecting tube fixed sections 12. The non-connecting tube fixed sections 12 are connected to both ends of the connecting tube fixed section 11. The connecting tube fixed section 11 and the non-connecting tube fixed section 12 are connected to form the middle section 1. The two regulating sections are connected through a horizontal connecting tube 251. The interior of the regulating section is hollow and has a certain air tightness. Both regulating sections are filled with liquid. The liquid in one regulating section can enter the other regulating section through the horizontal connecting tube 251.

[0061] Furthermore, the regulating section close to the flexible end 5 is the flexible end regulating section 3, and the regulating section close to the fixed end 4 is the fixed end regulating section 2. The fixed end regulating section 2 and the flexible end regulating section 3 are arranged on both sides of the middle section 1. One end of the fixed end regulating section 2 is butted against one end of the middle section 1, and the other end of the fixed end regulating section 2 is butted against the fixed end 4. One end of the flexible end regulating section 3 is butted against the other end of the middle section 1, and the other end of the flexible end regulating section 3 is butted against the flexible end 5. The regulating section 3 and the middle section 1, the middle section 1 and the fixed end regulating section 2, the fixed end regulating section 2 and the fixed end 4, the connecting pipe fixed section 11 and the non-connecting pipe fixed section 12 are all connected by flanges and bolts to form a whole steel support structure; the non-connecting pipe fixed sections 12 are evenly distributed on both sides of the connecting pipe fixed section 11, and the number of non-connecting pipe fixed sections 12 on both sides of the connecting pipe fixed section 11 is the same; an axial force meter is provided on the fixed end 4; the material of the horizontal connecting pipe 251 is PVC pipe or PPR pipe. The above settings can facilitate the assembly or disassembly of the steel support structure.

[0062] Furthermore, the upper side wall of the active end regulating section 3, the upper side wall of the connecting pipe fixed section 11, the upper side wall of the fixed end regulating section 2 and the upper side wall of the non-connecting pipe fixed section 12 are all provided with lifting points, and the three adjacent lifting points are used as lifting points for the crane to lift the steel support structure. The three lifting points are respectively a main lifting point 61 located in the middle and a left auxiliary lifting point 62 and a right auxiliary lifting point 63 located on both sides of the main lifting point 61; Fig.11 As shown, the horizontal distance between the left auxiliary suspension point 62 and the main suspension point 61 is d 1. The horizontal distance between the right auxiliary suspension point 63 and the main suspension point 61 is d 2. A main suspension rope 611 is provided on the main suspension point 61. The length of the main suspension rope 611 is H 1. A left auxiliary suspension point 62 is provided with a left auxiliary suspension rope 621, and the length of the left auxiliary suspension rope 621 is H 2. A right auxiliary suspension point 63 is provided with a right auxiliary suspension rope 631, and the length of the right auxiliary suspension rope 631 is H 3. By adjusting the length of the left auxiliary lifting rope 621 or the right auxiliary lifting rope 631, the steel support structure can be hoisted into the foundation pit in an inclined state, thereby realizing the steel support structure hoisting operation for the semi-covered subway station foundation pit; when the steel support structure is in a horizontal state, only the main lifting rope 611 is stressed, and the left auxiliary lifting rope 621 and the right auxiliary lifting rope 631 are both in a relaxed state, and the left auxiliary lifting rope 621 and the right auxiliary lifting rope 631 only play a protective role.

[0063] like Figure 2 As shown in the figure, when one side of the flexible end 5 is tilted downward for hoisting, the three lifting points are all set on the side close to the fixed end 4, the left auxiliary hoisting rope 621 plays the role of auxiliary hoisting, and the right auxiliary hoisting rope 631 plays the role of limiting vertical displacement, preventing the steel support structure from tilting too much on one side of the fixed end 4 during the horizontal adjustment process, thereby reducing the risk of the steel support structure during the hoisting process. H 2 is:

[0064] Formula (1)

[0065] In formula (1), H 1 is the length of the main suspension rope 611; d 1 is the horizontal distance between the left auxiliary suspension point 62 and the main suspension point 61; α It is the angle between the axis of the steel support structure and the horizontal plane during inclined lifting, that is, the inclination angle of the steel support structure when it is tilted and lifted into the pit.

[0066] When the flexible end 5 is tilted downward, the length of the right auxiliary lifting rope 631 is H 3 is:

[0067] Formula (2)

[0068] In formula (2), H 1 is the length of the main suspension rope 611; d 2 is the horizontal distance between the right auxiliary suspension point 63 and the main suspension point 61; ε is the vertical displacement limit value, (tan5° is the safety limit of the lifting inclination angle of the right auxiliary lifting rope 631);

[0069] When one side of the fixed end 4 is tilted downward for hoisting, the three lifting points are all set on the side close to the flexible end 5. The right auxiliary lifting rope 631 plays an auxiliary lifting role, and the left auxiliary lifting rope 621 plays a role in limiting the vertical displacement, preventing the steel support from tilting too much on the side of the flexible end 5 during the horizontal adjustment process, thereby reducing the risk of the steel support structure during the hoisting process; when one side of the fixed end 4 is tilted downward for hoisting, the length of the right auxiliary lifting rope 631 H 3 is:

[0070] Formula (3)

[0071] In formula (3), H 1 is the length of the main suspension rope 611; d 2 is the horizontal distance between the right auxiliary suspension point 63 and the main suspension point 61; α It is the angle between the axis of the steel support structure and the horizontal plane during tilted lifting, that is, the inclination angle of the steel support structure when tiltedly lifted into the pit;

[0072] When the fixed end 4 is tilted downward for hoisting, the length of the left auxiliary hoisting rope 621 is H 2 is:

[0073] Formula (4)

[0074] In formula (4), H 1 is the length of the main suspension rope 611; d 1 is the horizontal distance between the left auxiliary suspension point 62 and the main suspension point 61; ε is the vertical displacement limit value, (tan5° is the safety limit value of the lifting inclination angle of the left auxiliary lifting rope 621).

[0075] Through accurate calculation of the main lifting rope 611, the left auxiliary lifting rope 621 and the right auxiliary lifting rope 631, the steel support structure can be lifted into the pit at a set inclination angle, ensuring the smooth progress of the lifting operation, improving the lifting efficiency of the steel support structure, reducing the lifting risk and shortening the erection time.

[0076] Furthermore, if Figure 3 , Figure 5 and Figure 7As shown, the upper side wall of the middle part of the fixed end regulating section 2 is provided with a first regulating pipe opening 22, through which liquid can be injected into the interior of the fixed end regulating section 2, and outside air can enter the fixed end regulating section 2 through the first regulating pipe opening 22, and the air in the fixed end regulating section 2 can also be discharged through the first regulating pipe opening 22; a first electric-controlled valve 221 is provided on the first regulating pipe opening 22; the first electric-controlled valve 221 can be opened and closed wirelessly or wired, and the first electric-controlled valve 221 can accurately control the amount of liquid injected into the fixed end regulating section 2. The lower side wall of the middle part of the fixed end regulating section 2 is provided with a first drainage pipe opening 24 and a first connecting pipe opening 25, and a first manual valve 241 is provided on the first drainage pipe opening 24, and the first manual valve 241 can be opened to discharge the liquid inside the fixed end regulating section 2 through the first drainage pipe opening 24, and one end of the horizontal connecting pipe 251 is connected to the first connecting pipe opening 25.

[0077] like Figure 3 , Figure 6 and Figure 8 As shown, the upper side wall of the middle part of the flexible end regulating section 3 is provided with a second regulating pipe opening 32, through which liquid can be injected into the interior of the flexible end regulating section 3, and outside air can enter the flexible end regulating section 3 through the second regulating pipe opening 32, and the air in the flexible end regulating section 3 can also be discharged through the second regulating pipe opening 32; the second regulating pipe opening 32 is provided with a second electric-controlled valve 321, and the second electric-controlled valve 321 can accurately control the amount of liquid injected into the flexible end regulating section 3. The lower side wall of the middle part of the flexible end regulating section 3 is provided with a second drainage pipe opening 34 and a second connecting pipe opening 35, and the second drainage pipe opening 34 is provided with a second manual valve 341, and the second manual valve 341 can be opened to discharge the liquid inside the flexible end regulating section 3 through the second drainage pipe opening 34, and the other end of the horizontal connecting pipe 251 is connected to the second connecting pipe opening 35.

[0078] When the steel support structure is hoisted into the foundation pit in an inclined state, liquid is injected into the fixed end regulating section 2 using the first regulating pipe mouth 22, or liquid is injected into the interior of the flexible end regulating section 3 using the second regulating pipe mouth 32, so that the steel support structure can be quickly restored to a horizontal state, and then the steel support structure can be installed in the foundation pit, reducing the risk of erection and improving the efficiency of erection.

[0079] Furthermore, a fixing buckle 111 is provided on the lower side wall of the middle part of the connecting pipe fixed section 11, and an electrically controlled two-way liquid regulating pump 112 is provided on the horizontal connecting pipe 251. The electrically controlled two-way liquid regulating pump 112 is fixed on the fixing buckle 111. The electrically controlled two-way liquid regulating pump 112 can be opened and closed by wireless or wired control, and can accurately control the flow rate of the liquid; the electrically controlled two-way liquid regulating pump 112 can be used to adjust the liquid in the active end regulating section 3 and the fixed end regulating section 2, and then the horizontality of the steel support structure can be fine-tuned.

[0080] Further, a first air extraction pipe opening 23 is provided on the upper side wall of the middle part of the fixed end regulating section 2, and the first air extraction pipe opening 23 is connected to the first air extraction pump 231 through a hose; a second air extraction pipe opening 33 is provided on the upper side wall of the middle part of the flexible end regulating section 3, and the second air extraction pipe opening 33 is connected to the second air extraction pump 331 through a hose. After the steel support structure is hoisted into the foundation pit and restored to a horizontal state, it is necessary to fine-tune the horizontality of the steel support structure to ensure that the steel support structure is in a completely horizontal state. When it is necessary to lower the height of one end of the steel support structure close to the fixed end regulating section 2, turn on the electrically controlled two-way liquid regulating pump 112, and use the first air extraction pump 231 to evacuate the fixed end regulating section 2. Under the action of negative pressure, the liquid in the flexible end regulating section 3 can flow into the fixed end regulating section 2 through the horizontal connecting pipe 251, thereby increasing the gravity of the end of the steel support structure close to the fixed end regulating section 2, so that the end of the steel support structure close to the fixed end regulating section 2 is lowered until the steel support structure is in a completely horizontal state. When it is necessary to lower the height of the end of the steel support structure near the flexible end regulating section 3, the second vacuum pump 331 is used to evacuate the flexible end regulating section 3. Under the action of negative pressure, the liquid in the fixed end regulating section 2 can flow into the flexible end regulating section 3 through the horizontal connecting pipe 251, thereby increasing the gravity of the end of the steel support structure near the flexible end regulating section 3, causing the end of the steel support structure near the flexible end regulating section 3 to drop until the steel support structure is in a completely horizontal state. By adjusting the liquid in the fixed end regulating section 2 and the flexible end regulating section 3, the horizontality of the steel support structure can be fine-tuned to ensure the smooth progress of the erection construction.

[0081] The present invention can fine-tune the horizontality of the steel support structure in the following three ways:

[0082] (1) The first air pump 231 or the second air pump 331 is used in conjunction with the electrically controlled two-way liquid regulating pump 112 to control the horizontal or inclination of the steel support structure. The electrically controlled two-way liquid regulating pump 112 only controls the opening and closing of the horizontal connecting pipe 251.

[0083] (2) An electrically controlled two-way liquid regulating pump 112 is used to regulate the liquid in the fixed-end regulating node 2 and the flexible-end regulating node 3. That is, the electrically controlled two-way liquid regulating pump 112 can pump the liquid in the fixed-end regulating node 2 into the flexible-end regulating node 3, and can also pump the liquid in the flexible-end regulating node 3 into the fixed-end regulating node 2, so as to realize the horizontal or inclination control of the steel support structure.

[0084] (3) The combination of the first air extraction pump 231 and the electronically controlled two-way liquid regulating pump 112 or the combination of the second air extraction pump 331 and the electronically controlled two-way liquid regulating pump 112 is adopted to comprehensively regulate the horizontal or inclination of the steel support structure, preventing the failure of one of the first air extraction pump 231 and the second air extraction pump 331 from affecting the erection construction of the steel support structure and ensuring the smooth progress of the erection construction.

[0085] Further, first observation windows 21 are provided on both the front side wall and the rear side wall in the middle of the fixed-end regulating section 2, and second observation windows 31 are provided on both the front side wall and the rear side wall in the middle of the movable-end regulating section 3; oval transparent high-strength glasses 211 are embedded in both the first observation window 21 and the second observation window 31; the thickness of the glass 211 is A, and the wall thickness of the steel support structure is B, where 3 / 4B < A < B. As Fig. 9 shown, scale lines parallel to the axis of the steel support structure are provided on the glass 211, and the internal liquid level conditions of the fixed-end regulating section 2 and the movable-end regulating section 3 can be observed through the glass 211, and the levelness of the steel support structure can be judged based on the internal liquid level conditions.

[0086] The present invention also discloses an erection construction method for a controllable steel support structure of a semi-covered excavation subway station foundation pit. As Fig.12 shown, the erection construction method includes the following steps:

[0087] Step 1, determining the hoisting parameters: Determine the inclination angle α of the steel support structure for inclined hoisting into the pit, the positions of the three lifting points, and the length of the main lifting rope 611 according to the cover plate layout of the foundation pit H 1. Calculate the length of the left auxiliary lifting rope 621 through formula (1) or formula (4) H 2. Calculate the length of the right auxiliary lifting rope 631 through formula (2) or formula (3) H 3.

[0088] Step 2, assembling the steel support structure: Assemble the middle section 1, the fixed-end regulating section 2, the movable-end regulating section 3, the fixed end head 4, and the movable end head 5 outside the foundation pit to form the steel support structure;

[0089] Connect the first air extraction pump 231 to the first air extraction pipe orifice 23 on the fixed-end regulating section 2 through a hose, connect the second air extraction pump 331 to the second air extraction pipe orifice 33 on the movable-end regulating section 3 through a hose, close the first manual valve 241 and the second manual valve 341, and make preparations in advance for the subsequent step of injecting liquid and leveling the regulating section, and weld an axial force gauge on the fixed end head 4.

[0090] Step 3, tilted lifting into the pit: Use a crane and adopt a three-point lifting method with the main lifting point 61, the left auxiliary lifting point 62 and the right auxiliary lifting point 63 to lift the steel support structure into the foundation pit in an inclined state (the specific position of the lifting point and the length of each lifting rope are set according to step 1); due to the different gravity on both sides of the main lifting point 61, the steel support structure enters the semi-covered subway station foundation pit with one end tilted.

[0091] Step 4: Liquid injection and leveling: Open the first electrically controlled valve 221 and the second electrically controlled valve 321, close the electrically controlled two-way liquid adjustment pump 112, and calculate the liquid injection volume required to restore the steel support structure to a horizontal state according to the position of the main suspension point 61. V , according to the calculated injection volume V Liquid is injected into the regulating section (the fixed end regulating section 2 or the flexible end regulating section 3) on the side close to the main suspension point 61 to restore the steel support structure from an inclined state to a horizontal state.

[0092] like Fig.10 As shown, the water injection volume of the fixed end control section 2 and the flexible end control section 3 is calculated according to the on-site construction conditions. F is the tension at the main suspension point 61 when the steel support structure is horizontal, and the bending moment at the main suspension point 61 when the steel support structure is horizontal M = 0, the gravity of the liquid in the fixed end control section 2 and the flexible end control section 3 is approximated as a uniformly distributed load for calculation. The bending moment at the main suspension point 61 in the horizontal state M The calculation formula is as follows:

[0093] Formula (5)

[0094] In formula (5), q 1 is the unit length gravity of the steel support structure, N; q 2 is the gravity per unit length of the liquid in the fixed end regulating section 2 and the flexible end regulating section 3, N; G 1 is the gravity difference per unit length between the fixed end 4 or the movable end 5 near the main suspension point 61 and the steel support structure, N; G 2 is the gravity difference per unit length between the fixed end 4 or the movable end 5 on the side away from the main suspension point 61 and the steel support structure, N; is the length of the steel support structure, m; is the length of the flexible end 5 or the fixed end 4 on the side close to the main suspension point 61, The length of the flexible end regulating section 3 or the fixed end regulating section 2 close to the main suspension point 61, m; is the horizontal distance between the active end regulating section 3 or the fixed end regulating section 2 close to the main suspension point 61 and the main suspension point 61, m; d is the differential sign; ; .

[0095] The liquid filling volume of the fixed end control section 2 or the flexible end control section 3 close to the main suspension point 61 can be obtained by simplifying formula (5): V for:

[0096] Formula (6)

[0097] In formula (6), q 1 is the unit length gravity of the steel support structure, N; G 1 is the gravity difference per unit length between the fixed end 4 or the movable end 5 near the main suspension point 61 and the steel support structure, N; G 2 is the gravity difference per unit length between the fixed end 4 or the movable end 5 on the side away from the main suspension point 61 and the steel support structure, N; is the length of the flexible end regulating section 3 or the fixed end regulating section 2, m; The horizontal distance between the flexible end control section 3 or the fixed end control section 2 and the main suspension point 61, m; ρ is the liquid density, kg / m 3 .

[0098] Step 5, fine-tuning the horizontality: turn on the electrically controlled bidirectional liquid regulating pump 112 on the fixed section 11 of the connecting pipe, and connect the fixed end regulating section 2 with the flexible end regulating section 3 through the horizontal connecting pipe 251.

[0099] If one side of the fixed end 4 is to be moved downward, the first electrically controlled valve 221 on the fixed end regulating section 2 is closed, the second electrically controlled valve 321 on the flexible end regulating section 3 is opened, and the first vacuum pump 231 is used to evacuate air, so that the liquid in the flexible end regulating section 3 flows to the fixed end regulating section 2; if one side of the flexible end 5 is to be moved downward, the second electrically controlled valve 321 on the flexible end regulating section 3 is closed, the first electrically controlled valve 221 on the fixed end regulating section 2 is opened, and the second vacuum pump 331 is used to evacuate air, so that the liquid in the fixed end regulating section 2 flows to the flexible end regulating section 3;

[0100] The scale position of the glass 211 corresponding to the liquid inside the fixed-end regulating node 2 is observed through the first observation window 21, and the scale position of the glass 211 corresponding to the liquid inside the flexible-end regulating node 3 is observed through the second observation window 31. By adjusting the height of one side of the fixed end 4 or one side of the flexible end 5, the purpose of real-time fine-tuning of the horizontality of the steel support structure is achieved.

[0101] Step 6, place the steel support structure: place the steel support structure with the horizontal adjustment on the steel bracket on the purlin.

[0102] Step 7, apply axial force: According to the pre-stressed axial force calibration value designed and constructed according to the steel support structure, use hydraulic jacks to apply prestress to the steel support.

[0103] Step 8, dismantle the steel support structure: dismantle the steel support structure on the steel bracket, inject liquid into the flexible end regulating section or the fixed end regulating section to make the steel support structure in a tilted state, hoist the steel support structure out of the foundation pit, open the first manual valve 241 on the fixed end regulating section 2 to discharge the liquid in the fixed end regulating section 2, open the second manual valve 341 on the flexible end regulating section to discharge the liquid in the flexible end regulating section 3, and dismantle the first vacuum pump 231 and the second vacuum pump 331.

[0104] The construction method for erecting the steel support structure transforms the steel support structure and injects liquid into one end of the steel support to change the gravity on both sides of the steel support structure, so as to control the inclination angle of the semi-covered excavation steel support erection. The gravity difference between the liquid inside the fixed-end control section 2 and the flexible-end control section 3 is used to accurately control the inclination angle of the steel support structure during the hoisting process in real time, which provides a safe, convenient and efficient construction method for the erection of semi-covered excavation steel supports for subway stations. The ability to accurately control the hoisting inclination angle of the steel support structure in real time is of great significance to the erection of steel supports in semi-covered excavation foundation pit projects.

[0105] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0106] The invention discloses an adjustable steel support structure and an erection construction method for a semi-covered excavation of a subway station foundation pit, which can efficiently, safely and accurately complete the erection of steel supports, and can also conveniently carry out dismantling operations on the steel support structure, filling the gap of the lack of an effective, feasible and scientific method for erecting semi-covered excavation steel supports for subway station foundation pits. The erection construction method can adjust the horizontal inclination angle of the steel support structure in real time during the hoisting and erection process, and can greatly reduce the risk of the hoisting process by regulating the gravity of the steel support structure on both sides of the lifting point through liquid, and effectively solves the outstanding problems of irregular operation, high risk, low efficiency and long erection time when the existing gantry crane and excavator combination hoist the foundation pit steel support, and also realizes the real-time regulation of the hoisting inclination angle of the steel support structure during the erection process, which is of great significance to the field of hoisting and erection of steel supports for semi-covered excavation of subway stations.

[0107] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A semi-covered subway station foundation pit adjustable steel support structure, characterized in that: The steel support structure includes a flexible end, two regulating sections, an intermediate section and a fixed end, wherein: The movable end, one of the regulating sections, the middle section, another regulating section and the fixed end are connected in sequence; The intermediate section includes a connecting pipe fixing section and a plurality of non-connecting pipe fixing sections, wherein the non-connecting pipe fixing sections are connected to both ends of the connecting pipe fixing section, and the connecting pipe fixing section and the non-connecting pipe fixing section are connected to form the intermediate section; The two regulating sections are connected via a horizontal connecting pipe. The inside of the regulating section is hollow and filled with liquid. The liquid in one regulating section can enter the other regulating section through the horizontal connecting pipe. The regulating section close to the flexible end is the flexible end regulating section, and the regulating section close to the fixed end is the fixed end regulating section; The movable end and the movable end regulating section, the movable end regulating section and the intermediate section, the intermediate section and the fixed end regulating section, the fixed end regulating section and the fixed end, and the connecting pipe fixed section and the non-connecting pipe fixed section are all connected by flanges and bolts; The number of the non-connecting pipe fixing sections on both sides of the connecting pipe fixing section is the same; The fixed end is provided with an axial force meter; The horizontal connecting pipe is made of PVC pipe or PPR pipe. The upper side wall of the active end regulating section, the upper side wall of the connecting pipe fixed section, the upper side wall of the fixed end regulating section and the upper side wall of the non-connecting pipe fixed section are all provided with lifting points, and three adjacent lifting points are used as lifting points for a crane to lift the steel support structure, and the three lifting points are respectively a main lifting point in the middle and a left auxiliary lifting point and a right auxiliary lifting point on both sides; The horizontal distance between the left auxiliary suspension point and the main suspension point is d 1. The horizontal distance between the right auxiliary suspension point and the main suspension point is d 2. A main lifting rope is provided on the main lifting point, and the length of the main lifting rope is H 1. The left auxiliary lifting point is provided with a left auxiliary lifting rope, and the length of the left auxiliary lifting rope is H 2. The right auxiliary lifting point is provided with a right auxiliary lifting rope, and the length of the right auxiliary lifting rope is H 3. By adjusting the length of the left auxiliary lifting rope or the right auxiliary lifting rope, the steel support structure can be hoisted into the foundation pit in an inclined state; When the steel support structure is in a horizontal state, only the main suspension rope is stressed, and the left auxiliary suspension rope and the right auxiliary suspension rope are both in a relaxed state; When one side of the movable end is tilted downward for hoisting, the three hoisting points are all set on the side close to the fixed end, the left auxiliary hoisting rope plays a role of auxiliary hoisting, and the right auxiliary hoisting rope plays a role of limiting vertical displacement to prevent the reverse tilt angle of the fixed end side of the steel support structure from being too large during the horizontal adjustment process. At this time, the length of the left auxiliary suspension rope H 2 is: Formula (1) In formula (1), H 1 is the length of the main suspension rope; d 1 is the horizontal distance between the left auxiliary suspension point and the main suspension point; α It is the angle between the axis of the steel support structure and the horizontal plane during tilted lifting; The length of the right auxiliary lifting rope H 3 is: Formula (2) In formula (2), H 1 is the length of the main suspension rope; d 2 is the horizontal distance between the right auxiliary suspension point and the main suspension point; ε is the vertical displacement limit value, ; When one side of the fixed end is tilted downward for hoisting, the three hoisting points are all set on the side close to the flexible end, the right auxiliary hoisting rope plays a role of auxiliary hoisting, and the left auxiliary hoisting rope plays a role of limiting vertical displacement, so as to prevent the reverse tilt angle of the flexible end side from being too large during the horizontal adjustment process of the steel support structure; At this time, the length of the right auxiliary lifting rope H 3 is: Formula (3) In formula (3), H 1 is the length of the main suspension rope; d 2 is the horizontal distance between the right auxiliary suspension point and the main suspension point; α It is the angle between the axis of the steel support structure and the horizontal plane during tilted lifting; The length of the left auxiliary lifting rope H 2 is: Formula (4) In formula (4), H 1 is the length of the main suspension rope; d 1 is the horizontal distance between the left auxiliary suspension point and the main suspension point; ε is the vertical displacement limit value, .

2. The adjustable steel support structure for the semi-covered subway station foundation pit according to claim 1 is characterized in that: A first regulating nozzle is provided on the upper side wall of the middle part of the fixed end regulating section, through which liquid can be injected into the interior of the fixed end regulating section, and outside air can enter the fixed end regulating section through the first regulating nozzle; The first regulating pipe outlet is provided with a first electrically-controlled valve; the lower side wall of the middle part of the fixed-end regulating section is provided with a first drain pipe outlet and a first connecting pipe outlet, and the first drain pipe outlet is provided with a first manual valve. By opening the first manual valve, the liquid inside the fixed-end regulating section can be discharged through the first drain pipe outlet, and one end of the horizontal connecting pipe is connected to the first connecting pipe outlet.

3. The adjustable steel support structure for the semi-covered subway station foundation pit according to claim 2 is characterized in that: A second regulating pipe opening is provided on the upper side wall of the middle part of the flexible end regulating section, through which liquid can be injected into the interior of the flexible end regulating section, and outside air can enter the flexible end regulating section through the second regulating pipe opening; The second regulating pipe port is provided with a second electrically controlled valve; A second drain pipe outlet and a second connecting pipe outlet are provided on the lower side wall of the middle part of the active-end regulating section. A second manual valve is provided on the second drain pipe outlet. By opening the second manual valve, the liquid inside the active-end regulating section can be discharged through the second drain pipe outlet. The other end of the horizontal connecting pipe is connected to the second connecting pipe outlet.

4. The adjustable steel support structure for the semi-covered subway station foundation pit according to claim 3 is characterized in that: A fixing buckle is provided on the lower side wall of the middle part of the connecting pipe fixing section, and an electrically controlled two-way liquid regulating pump is provided on the horizontal connecting pipe, and the electrically controlled two-way liquid regulating pump is fixed on the fixing buckle; The electrically controlled bidirectional liquid regulating pump can be used to regulate the liquid in the two regulating nodes, thereby fine-tuning the horizontality of the steel support structure.

5. The adjustable steel support structure for the semi-covered subway station foundation pit according to claim 4 is characterized in that: A first air extraction pipe opening is provided on the upper side wall of the middle part of the fixed end regulating section, and the first air extraction pipe opening is connected to a first air extraction pump through a hose; A second air extraction pipe opening is provided on the upper side wall of the middle part of the flexible end regulating section, and the second air extraction pipe opening is connected to a second air extraction pump through a hose. By utilizing the first vacuum pump to evacuate air from the fixed-end regulating section, the liquid in the flexible-end regulating section can flow into the fixed-end regulating section through the horizontal connecting tube. By utilizing the second vacuum pump to evacuate air from the flexible-end regulating section, the liquid in the fixed-end regulating section can flow into the flexible-end regulating section through the horizontal connecting tube. By adjusting the liquids in the fixed-end regulating section and the flexible-end regulating section, the horizontality of the steel support structure can be fine-tuned.

6. The adjustable steel support structure for the semi-covered subway station foundation pit according to claim 5 is characterized in that: A first observation window is provided on the front side wall and the rear side wall of the middle part of the fixed end regulating section, and a second observation window is provided on the front side wall and the rear side wall of the middle part of the movable end regulating section; The first observation window and the second observation window are both embedded with glass; The thickness of the glass is A, the wall thickness of the steel support structure is B, 3 / 4B <A<B, The glass is provided with scale lines parallel to the axis of the steel support structure. The internal liquid levels of the fixed-end regulating joint and the movable-end regulating joint can be observed through the glass, and the horizontality of the steel support structure can be judged by the internal liquid levels.

7. A construction method for erecting an adjustable steel support structure for a semi-covered subway station foundation pit as claimed in claim 6, characterized in that: The installation method comprises the following steps: Step 1: Determine the lifting parameters: According to the layout of the foundation pit cover, determine the inclination angle α of the steel support structure, the positions of the three lifting points and the length of the main lifting rope. H 1. Calculate the length of the left auxiliary suspension rope using formula (1) or formula (4) H 2. Calculate the length of the right auxiliary suspension rope using formula (2) or formula (3) H 3; Step 2, assembling the steel support structure: assembling the middle section, the fixed end regulating section, the flexible end regulating section, the fixed end head, and the flexible end head outside the foundation pit to form a steel support structure; Connect the first vacuum pump to the first vacuum pipe port on the fixed end regulating section through a hose, connect the second vacuum pump to the second vacuum pipe port on the flexible end regulating section through a hose, close the first manual valve and the second manual valve, and weld an axial force gauge on the fixed end; Step 3, tilted hoisting into the pit: Use a crane and adopt a three-point hoisting method with the main hoisting point, the left auxiliary hoisting point and the right auxiliary hoisting point to hoist the steel support structure into the foundation pit in an inclined state; Step 4: Liquid injection and leveling: Open the first and second electronically controlled valves, close the electronically controlled two-way liquid adjustment pump, and calculate the liquid injection volume required to restore the steel support structure to a horizontal state based on the position of the main suspension point. V , according to the calculated injection volume V Inject liquid into the control section close to the main suspension point; Step 5, fine-tuning the horizontality: turn on the electrically controlled bidirectional liquid regulating pump on the fixed section of the connecting pipe, and connect the fixed end regulating section with the flexible end regulating section through the horizontal connecting pipe; If the fixed end is to be moved downward, the first electrically controlled valve on the fixed end regulating section is closed, the second electrically controlled valve on the flexible end regulating section is opened, and the first vacuum pump is used to evacuate air, so that the liquid in the flexible end regulating section flows to the fixed end regulating section; If one side of the flexible end is moved downward, the second electrically controlled valve on the flexible end regulating section is closed, the first electrically controlled valve on the fixed end regulating section is opened, and the second vacuum pump is used to evacuate air, so that the liquid in the fixed end regulating section flows to the flexible end regulating section; The scale position of the glass corresponding to the liquid inside the fixed end regulating section is observed through the first observation window, and the scale position of the glass corresponding to the liquid inside the flexible end regulating section is observed through the second observation window. By adjusting the height of one side of the fixed end or one side of the flexible end, the purpose of real-time fine-tuning of the horizontality of the steel support structure is achieved; Step 6, placing the steel support structure: placing the steel support structure with adjusted levelness on the steel bracket on the purlin; Step 7, applying axial force: according to the pre-stressed axial force calibration value of the steel support structure design and construction, a hydraulic jack is used to apply prestress to the steel support; Step 8, dismantle the steel support structure: dismantle the steel support structure, inject liquid into the flexible end control joint or the fixed end control joint to make the steel support structure in a tilted state, hoist the steel support structure out of the foundation pit, open the first manual valve on the fixed end control joint to drain the liquid in the fixed end control joint, open the second manual valve on the flexible end control joint to drain the liquid in the flexible end control joint, and dismantle the first vacuum pump and the second vacuum pump.

8. The method for erecting an adjustable steel support structure for a semi-covered subway station foundation pit according to claim 7, characterized in that: In step 4, the water injection amount of the fixed end regulating section and the flexible end regulating section is calculated according to the on-site construction conditions. F is the tension at the main suspension point when the steel support structure is in a horizontal state, and is the bending moment at the main suspension point when the steel support structure is in a horizontal state. M = 0, the gravity of the liquid in the fixed end control section and the flexible end control section is approximated as a uniformly distributed load for calculation, and the bending moment at the main suspension point in the horizontal state M The calculation formula is as follows: Formula (5) In formula (5), q 1 is the unit length gravity of the steel support structure, N; q 2 is the gravity per unit length of the liquid in the fixed end regulating section and the flexible end regulating section, N; G 1 is the gravity difference per unit length between the fixed end or the movable end close to the main suspension point and the steel support structure, N; G 2 is the gravity difference per unit length between the fixed end or the movable end on the side away from the main suspension point and the steel support structure, N; is the length of the steel support structure, m; is the length of the movable end or fixed end close to the main suspension point. is the length of the flexible end regulating section or the fixed end regulating section close to the main suspension point, m; The horizontal distance from the main suspension point to the active end regulating section or the fixed end regulating section close to the main suspension point, m; d is the differential symbol; ; ; The liquid filling volume of the fixed end control joint or the flexible end control joint close to the main suspension point can be obtained by simplifying formula (5): V for: Formula(6) In formula (6), q 1 is the unit length gravity of the steel support structure, N; G 1 is the gravity difference per unit length between the fixed end or the movable end close to the main suspension point and the steel support structure, N; G 2 is the gravity difference per unit length between the fixed end or the movable end on the side away from the main suspension point and the steel support structure, N; is the length of the active end regulating section or the fixed end regulating section, m; The horizontal distance between the active end control section or the fixed end control section and the main suspension point, m; ρ is the liquid density, kg / m 3 .

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