Foundation Pit Of Subway Station Research Articles

Study on dynamic response and safety control of reinforced concrete rigid frame structure under foundation pit blasting

Subway station is usually located in the dense area of urban buildings (structures). The blasting construction of subway station foundation pit is bound to have adverse effects on adjacent buildings (structures). Therefore, it is necessary to study the dynamic response of the building (structure) and propose the safety threshold of vibration velocity. Based on the foundation pit blasting project of Hejialong Station of Wuhan Rail Transit Line 12, the vibration monitoring of the field blasting test is carried out. Combined with LS-DYNA numerical simulation software, the dynamic response characteristics of a reinforced concrete rigid frame natatorium near the foundation pit are studied, and safety thresholds for structural vibration velocities are derived. It is worth noting that the structure is a large span reinforced concrete rigid frame structure, which is different from the general reinforced concrete frame structure. The safe allowable vibration velocity in the specification is not fully applicable to the structure. Therefore, it is necessary to focus on the dynamic response of the structure under the blasting effect and propose the safety threshold of structural vibration velocity, which can provide reference for the subsequent foundation blasting. The results are as follows: Blasting seismic waves in different propagation media, their energy attenuation is different. By analyzing the vibration velocity of reinforced concrete rigid frame structures, it is found that the high-level amplification effect occurred at specific height range. In addition, the vibration velocity changes abruptly at the parts where the shape and dimensions of the rigid frame cross-section change. The peak vibration velocity and the maximum principal stress of the concrete elements were statistically analyzed to obtain the linear relationship equation, and the vibration velocity safety control threshold of the structure was predicted to be V = 5.089 cm/s.

Exploration and Construction of Construction Technology for Integration of Foundation Pit of Subway Station and Adjacent Buildings

Exploration and Construction of Construction Technology for Integration of Foundation Pit of Subway Station and Adjacent Buildings

Research on Foundation Pit Monitoring and Management System Based on BIM+GIS+IOT

Since traditional foundation pit monitoring methods cannot meet the overall safety requirements of engineering, a foundation pit monitoring and management system based on BIM+GIS+IOT was proposed in this paper. BIM, GIS and Internet of Things were applied in the system. ESP32 chip and ESP-IDF framework were used to develop the IOT to complete the real-time collection and transmission of monitoring data, and the BIM and GIS model data is integrated and displayed by linking the information of the monitoring points and BIM model. The system then is used in the construction of a subway station foundation pit for environmental monitoring and early warning monitoring.

Dewatering Construction Technology for Foundation Pit of Subway Station

Dewatering Construction Technology for Foundation Pit of Subway Station

Analysis of Pit Corner Effect of Special-shaped Foundation Pit of Subway Station

Based on the deep foundation pit project of Maluan North Station of Xiamen Metro Line 2, a large number of monitoring points were set up to monitor the foundation pit in order to study the deformation law and the pit corner effect during the excavation of the special-shaped foundation pit. By analyzing on-site monitoring data and numerically simulating the excavation of special-shaped foundation pits, this study found that the lateral deformation of diaphragm wall and ground settlement at the corner of the pit all exhibited obvious pit corner effect. The maximum lateral displacement of the long-side diaphragm wall is slightly larger than that of the short-side diaphragm wall. The maximum ground settlement at the corner of the pit is less than the maximum ground settlement behind diaphragm wall. Moreover, the differential ground settlement around the pit corner is obvious.

Quality Evaluation and Applicability Analysis of TRD Method in Sand Stratum of Subway Station

Trench re-mixing and cutting deep method (TRD) construction is a rising method for building waterproof curtains in deep foundation pits, providing the advantages of large construction depth, widespread applicability to soil layers, and high quality of the cement-soil wall. Against the background of the Miaotou subway station foundation pit project through the quaternary system watery sand layer containing cohesive soil in Qingdao, the applicability of cement-soil wall constructed by the TRD method in Qingdao’s soft soil was researched. A comprehensive testing method which can evaluate the quality of the cement-soil wall was proposed. A series of field detection and laboratory tests that include borehole water pressure tests, borehole television imaging, electromagnetic wave borehole radar, and unconfined compressive strength test of the drilling core was completed. The test results show that the cement-soil wall had good integrity and continuity without weak tectonic zones. The average strength of the cement-soil wall ranged from 0.94 to 1.21 MPa, and the strength of the cement-soil wall at different depths existed large discreteness. However, it still met the design requirements of no less than 0.8 MPa. Test results showed that the permeability of the clay layer decreased from 10−5 to 10−7 cm/s and the permeability of the sand layer decreased from 10−2 to 10−7 cm/s. Both strength and permeability of the wall satisfied the design requirements for a watertight screen. The research results may provide reference for pit waterproof curtain engineering in similar sand stratum.

繁华路段地铁站深基坑变形规律研究

繁华路段地铁站深基坑变形规律研究

Research on Foundation Pit Construction Risk of Metro Station Based on Fuzzy Entropy Theory

There are many risks in the construction of Foundation Pit of Subway Station because of the complicated conditions and numerous factors influencing foundation pit construction. In order to reduce the construction risk, this paper firstly established the risk evaluation index system of subway station foundation pit construction, which includes seepage breaking, support instability, pit soil landslide, skirting damage, sudden surge damage and mechanical wounding (six first - level indicators, seventeen secondary indicators);Then, the fuzzy entropy theory is applied to calculate the weight of each index, and the construction risk evaluation model of subway station foundation pit is established. Finally, taking LingBin road subway station foundation pit construction in Tianjin as an example, the construction risk of the pit foundation project was evaluated, the evaluation results provide a good basis for the construction risk prevention of the foundation pit.

Analysis of Deep Foundation Pit of Subway Station

According to the engineering characteristics,the project was divided into four typical operating conditions,the deformation rules of deep foundation pit at subway station in tunneling are studied with the method of FLAC3D numerical simulation,the supporting structures choose by the bored piles and interior support. The analysis of the horizontal deformation of the retaining structures,the axial force changes of steel support,the settlement law and the influence sphere of surrounding soil. For installation of prop structures on the performance of deep excavations is investigated through numerical analysis with site specific subsurface conditions,The conclusion in this paper can provides reference for the reasonable design and safety construction of deep foundation pit.

Numerical Analysis of the Deformation Law of Deep Foundation Pit of Subway Station by FLAC3D

Taking the deep foundation pit engineering of a Subway Station as background. The paper introduces the projects surroundings,geological and hydrological conditions of the proposed field and the retaining structural type. According to the engineering characteristics,the project was divided into four typical operating conditions,the deformation rules of deep foundation pit at subway station in tunneling are studied with the method of FLAC3D numerical simulation,the supporting structures choose by the bored piles and interior support. The analysis of the horizontal deformation of the retaining structures, the settlement law and the influence sphere of surrounding soil. The conclusion in this paper can provides reference for the reasonable design and safety construction of deep foundation pit.

Design of Enclosure for Subway Station Foundation Pit in Southward Extension Line of Chengdu Metro Line One

This paper summarizes the design of open-cut subway station in Chengdu Metro line one. The station is built by cut and cover method and divided into three special parts with four different cross-sections used for main line and transfer track. Such retaining techniques as bored piles, steel pipe struts, soil nails, rock-bolts, steel-meshes, shotcrete and anchored steel cables are comprehensively used to maintain the stability of foundation pit. The anti-buoyancy coefficient of the open cut station is also derived and attains the requirement of safety and stability for the foundation pit after the utilization of these enclosure measures. The application of the design and construction technique for the subway station may provide guidance for the building of analogous subway station under similar geological and hydrogeological conditions in Chengdu.

Analysis of Surveillance for Deep Foundation Pit of Subway Station

Deep foundation pit of subway station project are affected by the geological conditions with rich water and sand seriously. So the construction has a greater difficulty. We have to analyze the measured data and study on the deformation law of retaining structure and soil. That can be used as theoretical verification about the design scheme of retaining structure. The results show that this design scheme can be used as the support form in the similar geological conditions.