阅读说明：本技术 一种基于受限空间的地铁绿色建造施工调适方法 (Subway green construction adjustment method based on limited space ) 是由 丁研 鄢睿 宿皓 王智垚 于 2019-09-24 设计创作，主要内容包括：本发明公开一种基于受限空间的地铁绿色建造施工调适方法,包括以下步骤：步骤(1)围护结构施工；步骤(2)桩基托换保护系统；步骤(3)受限空间桩基托换；步骤(4)大体积预应力托换；步骤(5)桩基托换应力转换；步骤(6)绿色施工技术。研究地铁绿色建造技术能探索出相关地铁施工过程中的节能以及环保的相关技术,为日后相关的工程提供宝贵的经验,对气候条件类似地区地铁建造技术具有指导意义。(The invention discloses a subway green construction adjustment method based on a limited space, which comprises the following steps of: step (1), constructing a building enclosure; step (2) pile foundation underpinning protection system; step (3) underpinning the pile foundation in the limited space; step (4) large-volume prestress underpinning; step (5) pile foundation underpinning stress conversion; and (6) green construction technology. The research on the green subway construction technology can explore the energy-saving and environment-friendly related technologies in the related subway construction process, provide valuable experience for related projects in the future, and have guiding significance on the subway construction technology in areas with similar climatic conditions.)

1. A subway green construction adjustment method based on a limited space is characterized by comprising the following steps:

step (1), constructing a building enclosure;

step (2) pile foundation underpinning protection system;

step (3) underpinning the pile foundation in the limited space;

step (4) large-volume prestress underpinning;

step (5) pile foundation underpinning stress conversion;

and (6) green construction technology.

2. The adaptation method for green construction of subways based on limited space as claimed in claim 1, wherein the building envelope construction of step (1) is as follows: the method adopts a method of adding a waterproof curtain outside the secant pile to replace the originally designed underground continuous wall, uses a percussion drill to form a hole on the secant pile, mutually sects the plain concrete pile and the reinforced concrete bored pile, and uses a method of wss grouting at the joint of the pile wall outside the foundation pit to meet the requirement of water stopping.

3. The adaptation method for green construction of subways based on limited space as claimed in claim 1, wherein the pile foundation underpinning protection system in the step (2) specifically comprises: in the early construction of pile foundation underpinning, the steel bars are dug out of the existing bearing platform, 6 long steel beams are erected under the ramp bridge deck, and the shaped steel beam foundation is a full-hall fastener scaffold.

4. A restricted space-based adaptation method for green construction and construction of a subway as claimed in claim 1, wherein said step (3) of underpinning the pile foundation in the restricted space is to underpin the original bridge pier pile foundation by means of 4 prestressed concrete beams by making the pile foundation intrude into the main body of the station, and to cut off the existing pile foundation.

5. The adaptation method for green construction of subways based on limited space as claimed in claim 1, wherein said step (4): the large-volume prestress underpinning specifically comprises the following steps: pile foundation underpinning engineering sets 4 drilled piles distributed on the north and south sides of the enclosure structure, a prestressed concrete beam is applied in the middle to completely wrap the original bridge bearing platform, meanwhile, underpinning pile heads to corresponding elevations, jacks are arranged before the pile heads are poured, and post-pouring sections are reserved;

before the underpinning beam is poured, the wrapping parts of the existing ramp bridge bearing platforms, piles and the like which are newly made the underpinning beam are subjected to scabbling and rib planting treatment, and the underpinning beam is poured.

6. The adaptation method for green construction of subways based on limited space as claimed in claim 1, wherein said step (5): the large-volume prestress underpinning specifically comprises the following steps:

(1) after the underpinning beam concrete reaches the strength, symmetrically placing 2 jacks in advance on each underpinning pile top, applying jacking counter force by using the jacks, and unloading the jacking counter force to a state that the pile body stress of the barrier pile to be cut off is equal to zero after the underpinning pile foundation is settled and stabilized; when the jacks jack up, the eight jacks synchronously jack up;

(2) sawing off pier stud reinforcing steel bars and concrete in the horizontal direction at a position 0.5m below the bottom of a newly-made underpinning beam, firstly sawing off the pier stud reinforcing steel bars in the circumferential direction, and then gradually sawing off core concrete;

(3) along with main part foundation ditch excavation, chiseling out original barrier pile one by one according to the preface.

7. The adaptation method for green construction of subways based on limited space as claimed in claim 1, wherein the green construction technology of step (6) is specifically: the generated slurry is pumped, discharged and transported out for centralized treatment by adopting a sewage suction truck, and the wastewater generated by equipment cleaning and site cleaning is discharged to a municipal rainwater well with drainage capacity through a three-stage sedimentation tank; in terms of noise, the construction site monitors the noise, and particularly stops construction when the noise exceeds the requirement at night; in the aspect of structure detection, the original materials of the steel bars, the connection mode and the concrete strength for construction all meet the design requirements.

Technical Field

The invention belongs to the field of rail transit construction, relates to a pile foundation underpinning technology under a limited space working condition, and particularly relates to a subway green construction adjustment method based on a limited space.

Background

In order to expand urban underground space, the construction of a multidimensional and three-dimensional urban underground rapid passage traffic network becomes an important way for relieving traffic transportation pressure in urban core areas, subways are used as one of the most main forms of underground traffic, and the construction space 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 green construction generally comprises the aspects of construction unit organization and planning, construction site comprehensive management, construction waste treatment, pollution control and the like. The main contents of pollution control among these are: noise pollution, water pollution, light pollution, and the like. The green construction not only ensures the efficiency and quality of engineering construction, but also reduces the energy consumption rate and improves the surrounding ecological environment.

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

In order to overcome the defects of the prior art, the invention provides a subway green construction adjustment method based on a limited space, which is suitable for pile foundation underpinning construction in the limited space, and is particularly suitable for construction under the condition that a subway line conflicts with an overpass pile foundation and the surrounding environment is not influenced.

In order to achieve the purpose, the invention adopts the following technical scheme: a subway green construction adjustment method based on a limited space comprises the following steps:

step (1): the construction of the enclosure structure is a precondition of underpinning system construction, the method proposes that the original designed underground continuous wall is replaced by a method of adding a waterproof curtain to the secant pile, the secant pile is formed into a hole by using a percussion drill, the plain concrete pile and the reinforced concrete bored pile are mutually occluded, and a wss grouting method is used at the joint of the pile wall outside the foundation pit so as to meet the requirement of water stopping. And optimizing the construction process of the low-clearance enclosure structure, controlling the pile-forming quality and determining the water stopping mode in an experimental mode.

Step (2) pile foundation underpinning protection system: in the early construction of pile foundation underpinning, the embedded steel bars need to be dug out of the existing bearing platform, 6 long steel beams are erected under the bridge floor of the ramp bridge in order to ensure that the ramp bridge cannot be damaged due to overlarge settlement in the construction process and the underpinning process, and the shaped steel beam foundation is a full-space fastener scaffold, so that the safety of the existing bridge is ensured.

And (3) underpinning the pile foundation in the limited space, namely underpinning the original pile foundation of the pier by adopting 4 prestressed concrete beams through invading the pile foundation into the station main body, and cutting off the existing pile foundation.

And (4) carrying out large-volume prestress underpinning, wherein 4 drilled piles are arranged in the pile foundation underpinning project and distributed on the north and south sides of the building envelope, a prestressed concrete beam is applied in the middle to completely wrap the original bridge bearing platform, the pile head of the underpinning pile is chiseled to a corresponding elevation, a jack is arranged before the pile head is poured, and a post-pouring section is reserved. Before the underpinning beam is poured, the wrapping parts of the existing ramp bridge bearing platforms, piles and the like which are newly made the underpinning beam are subjected to scabbling and rib planting treatment, and the underpinning beam is poured. The construction of the contact surfaces of the new pile foundation and the old pile foundation is strictly controlled, and the construction quality of the underpinned beam in the new construction is ensured.

And (5) carrying out underpinning stress conversion on the pile foundation, after the underpinning beam concrete reaches the strength, symmetrically placing 2 jacks in advance on each underpinning pile top, applying jacking counter force by using the jacks, and unloading the jacking counter force to a state that the pile body stress of the barrier pile to be cut is equal to zero after the underpinning pile foundation is settled and stabilized. When the jacks jack up, the eight jacks simultaneously and synchronously jack up. And sawing off the pier column reinforcing steel bars and the concrete in the horizontal direction at a position 0.5m below the bottom of the newly-made underpinning beam, firstly sawing off the pier column reinforcing steel bars in the circumferential direction, and then gradually sawing off the core concrete. Along with main part foundation ditch excavation, chiseling out original barrier pile one by one according to the preface.

Step (6), green construction technology: the green construction technology runs through the whole green building system, the generated slurry is pumped, discharged and transported out for centralized treatment by adopting a sewage suction truck, and the wastewater generated by equipment cleaning and site cleaning is discharged to a municipal rainwater well with drainage capacity through a three-stage sedimentation tank; in terms of noise, the construction site monitors the noise, and particularly, at night, the construction is stopped when the sound intensity exceeds the requirement; in the aspect of structure detection, the original materials of the steel bars, the connection mode and the concrete strength for construction all meet the design requirements.

The details of the construction technology of the enclosure structure in the step (1) are shown in the attached figure 1, and the concrete steps are as follows:

for a limited space formed by a main body structure of a subway station and a overpass passing through the underground, the distance between the bottom of the overpass and the existing ground is lower, the overpass is limited by clearance below the overpass, the conventional slot machine construction is not convenient for working conditions with a ground connecting wall, if a drilling pile machine is adopted for forming a slot and a construction scheme of lowering the ground connecting wall reinforcement cage in sections is adopted, the reinforcement cage is difficult to hoist and connect, the construction risk is higher, the hole collapse is easy, and the implementation is not easy, so that the original designed underground continuous wall is replaced by a method of adopting an occlusive pile and a water-stop curtain, and water is stopped outside the pile by adopting a wss grouting method due to.

The conventional rotary drilling rig does not meet the low-clearance construction environment, the method is used for the secant pile in a hole forming mode of a percussion drill, the construction process of the low-clearance building envelope is optimized, the pile forming quality is controlled, and the water stopping mode is determined in an experimental mode.

The schematic diagram of the pile foundation underpinning protection system in the step (2) is shown in the attached figure 2, and the concrete steps are as follows:

1) system for establishing settlement and deformation monitoring of existing bridge structure

2) Underpinning underground continuous wall and crown beam

3) Underpinning new pile and foundation pit fender pile by adopting pile foundation back-pressure grouting technology

4) And (3) adopting a temporary steel frame for supporting the bridge pier except the existing linear bridge crossbeam, and installing a jack.

And (3) carrying out the pile foundation underpinning technology on the limited space, wherein the construction schematic diagram is shown as an attached drawing 3, and the main steps are as follows.

1) And (5) excavating a foundation pit for underpinning the pile foundation, and excavating the underground 1-2m of the planted underpinned beam.

2) And performing chiseling and chiseling on the surfaces of a bearing platform, a pile foundation and a pier of which the pier is positioned in the range of the underpinned beam by adopting sawtooth-shaped chiseling.

3) And d, planting bars in the scabbling areas of the existing bearing platforms, the pier columns and the pile foundations.

4) And painting epoxy emulsion cement slurry for interface treatment.

The large-volume prestress underpinning technology in the step (4) has a specific construction schematic diagram as shown in the attached figure 4, and comprises the following specific steps.

1) And binding the steel bars of the cast-in-place section of the underpinning beam and the pile foundation, and pre-embedding steel plates at the positions of the jack and the steel support pad.

2) Erecting a bracket and a vertical template at the positions of foundation pits at two ends of the underpinning beam

3) Concrete for pouring underpinned beam and pile foundation in first-pouring section

4) Installing jacks on underpinned piles and underpinned supports, and installing and debugging

5) System for monitoring stress strain and displacement of underpinning system

6) Tensioning and underpinning the prestressed steel beams in batches, carrying out graded loading and jacking on the jack, applying pressure to the underpinned pile, and locking the self-locking of the jack after the underpinned pile is loaded to the designed load and deforms stably.

And (5) pile foundation underpinning stress conversion, wherein the specific construction schematic diagram is shown as an attached drawing 5, and the specific steps are as follows.

1) After the jack is set, the steel upright post is placed to complete the conversion of the load from the old pile to the new pile.

2) And cutting off the old pile, and gradually unloading the jack to zero.

3) And welding the pile top and the corresponding pre-embedded steel bars of the joist, and pouring C50 micro-expansion concrete into the jacking space between the beam bottom and the pile top to complete the rigid connection between the underpinning beam and the underpinning pile.

4) Except the waterproof area already applied to the bottom of the middle part of the underpinning beam, the outer package of the rest parts of the underpinning beam is subjected to waterproof construction.

5) And continuing to perform coordination construction of the main pit foundation, and dismantling the steel support after the coordination construction is completed.

6) And establishing a later-stage detection system until the construction of the station main body is completed.

The step (6) is a green construction technology, the specific content is shown in figure 6, and the main steps are as follows.

1) PM2.5 green construction control technology, through combining on-the-spot particulate matter concentration detection, the dustproof technological means in the green construction of analysis comparison subway, research dustless management's suitability technique and method mainly can be divided into three parts of the dust suppression technique of keeping out the wind, spraying dustproof technique and novel environmental protection device.

2) The noise green construction control technology is combined with on-site noise detection, discriminative analysis is carried out on the principle of noise formation in the construction process, and a targeted solution is researched. After the noise source is located, the high frequency and low frequency noise are denoised respectively.

3) The decrement control technology of construction wastes, a targeted construction site waste control scheme should be formulated in subway construction, on one hand, the influence on the environment due to production and transportation of updated required materials is reduced, and on the other hand, building material remainders are used to the maximum extent, and concrete and mortar are scientifically utilized and scattered.

Advantageous effects

The invention analyzes and explores the related benefits which can be produced by the green construction of the subway, and comprises the following steps:

social benefits are as follows: the construction process avoids the damage to the surrounding environment, improves the traffic organization in the construction process, and builds and operates the integrated management technology to avoid the influence on the normal life and road traffic of surrounding residents as much as possible. Meanwhile, by means of resident evaluation, whether the attitude and satisfaction degree of surrounding residents on subway construction are improved by reducing the influence on the surrounding resident environment due to the utilization of the green construction technology is researched;

economic benefits are as follows: the construction process adopts the technologies of pile foundation underpinning, foundation pit supporting, dewatering, prefabricating and assembling and the like, thereby saving building materials and reducing construction cost; the production cost in the construction process is saved by using the technical mode of water and energy conservation. And evaluating the economic benefit of the green construction technology of the subway by using the cost-to-efficiency ratio.

Environmental protection benefit: the subway green construction technology adopts the related water-saving and energy-saving technology and the technology for controlling waste materials and atmospheric pollutants, reduces the atmospheric PM10 content of the construction environment, avoids the harmful emission of the waste materials as much as possible, and improves the recycling rate of the waste materials. The environmental protection benefit of the green construction technology is measured by indexes such as PM10 concentration, material saving rate, waste recovery rate and the like.

Comprehensive benefits are as follows: the research on the green subway construction technology can explore the energy-saving and environment-friendly related technologies in the related subway construction process, provide valuable experience for related projects in the future, and have guiding significance on the subway construction technology in areas with similar climatic conditions.

Drawings

Fig. 1 is a schematic view of the construction of the enclosure structure.

Fig. 2 is a schematic construction diagram of a pile foundation underpinning protection system.

Fig. 3 is a schematic diagram of limited space pile foundation underpinning construction.

FIG. 4 is a schematic view of a large-volume prestressed underpinning construction.

Fig. 5 is a schematic diagram of pile foundation underpinning stress conversion construction.

FIG. 6 is a flow chart of the green construction technique.

FIG. 7 is a construction site view of the enclosure according to the embodiment.

Fig. 8 is a site view of pile foundation underpinning protection construction according to the embodiment.

FIG. 9 is a site diagram of pile foundation underpinning stress conversion construction according to the embodiment.

Detailed Description

The invention is further illustrated by the following specific examples and the accompanying drawings. The examples are intended to better enable those skilled in the art to better understand the present invention and are not intended to limit the present invention in any way.

The invention discloses a method for adjusting green construction and adaptation of a subway in a limited space, which comprises the following steps of:

step (1): the construction of the enclosure structure, the method proposes that the original designed underground continuous wall is replaced by a method of adding a waterproof curtain to the secant pile, the secant pile is formed into a hole by using a percussion drill, the plain concrete pile and the reinforced concrete bored pile are mutually seceded, and wss grouting is used at the joint of the pile wall outside the foundation pit so as to meet the requirement of water stop.

Step (2) pile foundation underpinning protection system: 6 steel long steel beams are erected below the ramp bridge deck, and the shaped steel beam foundation is a full fastener scaffold, so that the safety of the existing bridge is guaranteed.

And (3) underpinning the pile foundation in the limited space, namely underpinning the original pile foundation of the pier by adopting 4 prestressed concrete beams through invading the pile foundation into the station main body, and cutting off the existing pile foundation.

And (4) carrying out large-volume prestress underpinning, wherein pile foundation underpinning engineering is provided with 4 drilled piles distributed on the north and south sides of the enclosure structure, a prestressed concrete beam is applied in the middle, and a jack is arranged before pile heads are poured. And (4) roughening and embedding ribs on the newly-made underpinned beam wrapping parts of the existing ramp bridge bearing platform, piles and the like, and pouring the underpinned beam.

And (5) carrying out underpinning stress conversion on the pile foundation, after the underpinning beam concrete reaches the strength, symmetrically placing 2 jacks in advance on each underpinning pile top, applying jacking counter force by using the jacks, and unloading the jacking counter force to a state that the pile body stress of the barrier pile to be cut is equal to zero after the underpinning pile foundation is settled and stabilized. And sawing off the pier column reinforcing steel bars and the concrete in the horizontal direction at a position 0.5m below the bottom of the newly-made underpinning beam, firstly sawing off the pier column reinforcing steel bars in the circumferential direction, and then gradually sawing off the core concrete. Along with main part foundation ditch excavation, chiseling out original barrier pile one by one according to the preface.

Step (6), green construction technology: the mud generated by construction is pumped, discharged and transported out for centralized treatment by adopting a sewage suction truck, and the wastewater generated by equipment cleaning and site cleaning is discharged to a municipal rainwater well with drainage capacity through a three-stage sedimentation tank; monitoring noise on a construction site, and stopping construction when the noise exceeds the requirement; in the aspect of structure detection, the original materials of the steel bars, the connection mode and the concrete strength for construction all meet the design requirements.