In the field of building construction, the closed protection and environmental control of pit operation has always been a problem in the industry. Beijing Xinyuan Yijia Membrane Structure Technology Co., Ltd. has been ploughing into membrane structure technology for many years, and has developed many generations and types of air membrane products for pits in response to the diversified needs of pit construction scenarios, ranging from the early fully enclosed basic models to the upgraded models incorporating intelligent temperature control to the customised models adapted to special scenarios, forming a product matrix covering different construction needs and providing key solutions for the greening, securing and efficient construction of pits. It has formed a product matrix covering different construction needs, providing key solutions for green, safe and efficient pit construction.

Today, I will give you a systematic inventory of Xinyuan's five major types of pit air film and its application practice.I. Pit Air Membrane 1.0: "Basic Benchmark" of Fully Enclosed Air Bearing Structure

As the initial core model of Xinyuan's air membrane pit protection products, Pit Air Membrane 1.0 takes "fully closed air bearing type" as its core structure, supporting the entire membrane form by air pressure without the need for complex supports of traditional steel structure, and realising rapid closure and coverage of the pit space.

The core advantage of this kind of pit air membrane is strong sealing and large span of coverage, which can effectively isolate the air circulation inside and outside the pit, reduce the diffusion of dust and noise leakage, and at the same time resist the impact of wind, rain, low temperature and other bad weather on the construction.

In practical application, pit air membrane 1.0 has landed in several key projects. For example, in the pit project of Hebei Medical University, which has a large pit area and a long construction period, Xinyuan Air Membrane has realised the full-cycle closure of the pit through the customised 1.0 Air Membrane, effectively controlling the impacts of construction dust on the surrounding hospitals and the campus environment, and safeguarding the normal order of medical treatment, teaching and life; and the pit project of Daxing Hexi District, Beijing, faces a complex urban surrounding environment. The rapid construction and efficient closure of 1.0 Air Membrane not only shortened the preparation time of the project, but also adapted to the irregular contour of the pit through the modular design, becoming an "environmental barrier" for the pit construction in the core area of the city.

Air-ribbed pits: "Flexible upgrade" of the fully enclosed air-ribbed structure.

Compared with the 1.0 air-bearing structure, the air-ribbed pit air membrane developed by Xinyuan Air Membrane has achieved innovation in the support method - taking "air rib" as the core load-bearing component, replacing the traditional bracket by the ribbed structure formed by inflating, and then covering the sealed membrane on both sides to form a fully enclosed space. Then the two sides are covered with a sealed membrane to form a fully enclosed space. The advantage of this structure is that the force is more uniform, the overall stability of the membrane is stronger, and it can be adapted to the narrow and long pit scene. The modular design of the air ribs makes it easier to disassemble the membrane, and the combination of membrane and air ribs can be better adapted to the stage-by-stage adjustments required in pit construction.

The Baohuari project in Beijing's Dongcheng District is the first application case of air-ribbed pit air membrane. The project is located in the core of Beijing's old city, with dense buildings and narrow space around the pit, making it difficult to build a traditional closed structure. Xinyuan Air Membrane customised the air-ribbed pit air membrane to meet the characteristics of the project. By avoiding the obstacles of the surrounding buildings through the flexible layout of the air ribs, Xinyuan Air Membrane completed the construction of the air membrane and inflated the air membrane for debugging in only 3 days, achieving the full closure of the pit. During the construction process, the wind load and snow load resistance of the air-ribbed structure was fully verified, which effectively guaranteed the safety of the pit operation and avoided the interference of the construction with the neighbouring residents' lives.

Mobile track-type pit air film: "Dynamic adaptation" of track + air rib structure

In response to the demand for "staged operation and repeated movement of the closed body" in the construction of linear pits such as subways and tunnels, Xinyuan Air Membrane has developed a movable track-type air membrane for pits - with the core of "track + fully enclosed air rib structure", the air membrane body is equipped with pulley components at the bottom and can be moved along the preset pits on both sides. With "rail + fully enclosed air rib structure" as the core, the air film body is installed with pulley components at the bottom, which can slide freely along the pre-set rails on both sides of the pit to achieve flexible adjustment of the enclosed area.

Jinan Metro Line 7 Long'ao Building Station project is a representative application of this type of air membrane. Metro pit construction is characterised by "segmental excavation and segmental support", and the traditional fixed closed structure needs to be dismantled and installed repeatedly, which is not only time-consuming and labour-intensive, but also increases the construction cost. Xinyuan Air Membrane customised a movable track-type air membrane for this project, the length of which is adapted to the needs of segmental operation of the pit, and the sliding of the track can quickly transfer the closed area to a new construction section, without the need to repeat the construction of the membrane, and only need to adjust the fixed point of the track to complete the switch of position. This solution not only shortens the time of each closure adjustment, but also reduces the loss of membrane material and lowers the comprehensive cost of the project, becoming an "efficient solution" for linear pit construction of the metro.

IV. Pit Air Membrane 2.0: "Experience Innovation" with Active Temperature Control Technology

As the requirements of pit construction for the comfort of the working environment increase, Xinyuan Air Membrane has launched Pit Air Membrane 2.0 by integrating "active water circulation cooling technology + heat-insulating mesh membrane material" on the basis of the 1.0 fully-closed air-bearing structure, realising the upgrade from "closed protection" to "intelligent temperature-control protection". "Intelligent temperature control protection" upgrade.

It not only chooses the three-layer heat-insulating mesh membrane material to reduce the heat accumulation inside the membrane, but also equips the active water circulation cooling system, which takes away the heat of the outdoor air through the flow of the circulating water, so that the temperature of the air conveyed by the fan to the membrane can be significantly reduced, which effectively improves the high-temperature and stuffy working environment inside the pit in the summer.

The Wangtan pit project in Beijing was the first application of Xinyuan's Pit Air Membrane 2.0. The construction cycle of this project spanned the summer, and the temperature inside the traditional pit enclosure often exceeded 40°C, which could easily lead to heatstroke among the construction personnel and affect the operational efficiency. After Xinyuan Air Membrane 2.0 was put into use, through the synergistic effect of the active water circulation cooling system and the heat-insulating membrane, the temperature inside the membrane was nearly the same as that outside, which significantly improved the comfort of the construction workers, and the average daily construction efficiency of the project was increased by 15%.

Semi-enclosed air-ribbed pit air membrane: "customised solutions" for local conditions.

In response to the demand of "needing closed protection but not fully closed heat preservation, and needing to enhance air circulation" in the pit construction in some areas, Xinyuan Air Membrane has launched the semi-closed air-ribbed pit air membrane. That is to say, the air rib type is the core structure, but the "mountain wall" of the traditional air membrane is cancelled, forming a semi-closed form of "closed on both sides and the top, and open at both ends", which can ensure the protection of the top and sides of the pit and at the same time, achieve the natural circulation of the air at both ends and reduce the humidity and temperature inside the membrane. temperature inside the membrane.

Singapore pit air membrane project is a typical practice of this type of product. Singapore has a tropical maritime climate with high temperature and rainy weather throughout the year. The pit construction needs to prevent rainwater from pouring in and dust from spreading, but also needs to avoid high temperature and high humidity inside the membrane caused by full closure, and also needs to ensure the passage efficiency of large-scale construction equipment. In response to the local climate characteristics, Xinyuan Air Membrane has customised a semi-closed air-ribbed air membrane for pits: the air-ribbed structure guarantees the membrane's ability to resist wind and rain in rainy weather, and the closed membrane at the top prevents rainwater from pouring into the pits; and the open design of the two ends takes advantage of the year-round sea breeze in Singapore to realise the natural ventilation inside the membrane, so that a comfortable working environment inside the membrane is maintained without the need for additional installation of ventilation equipment. This solution not only meets the local climate requirements, but also reduces transport and construction costs through lightweight design, making it a typical case of "international adaptation" of Xinyuan's air membrane technology.

From the basic closure of pit air membrane 1.0 to the intelligent temperature control of 2.0; from the general-purpose model with full closure to the customised model with movable and semi-closure, the five types of pit air membrane of Xinyuan Air Membrane have always been guided by the core of "project demand", and have continuously solved the pain point problems in pit construction through structural innovation and technology integration. These products have not only proved their reliability in many key projects in China, but have also successfully entered the international market, demonstrating the innovative strength of China's air membrane technology.

In the future, with the further enhancement of green and intelligent requirements for building construction, Xinyuan Air Membrane will incorporate more intelligent monitoring and energy consumption optimisation technologies into the pit air membrane, continue to lead the industry's technological upgrading, and provide better protection solutions for global pit construction.