Finite Element Research of Self-Supporting Technology in Construction of Underground Structures Adjacent to Existing Buildings

Author(s):  
Wang Yun ◽  
Yao Jitao ◽  
Yan Yuting ◽  
Shang Xuguang
Vestnik MGSU ◽  
2020 ◽  
pp. 452-461
Author(s):  
Emil Imran Оglu Alirzaev ◽  
Marina E. Dement'eva

Introduction. One of the serious problems in the construction of underground structures in a dense urban area is the occurrence of excess deformations of the foundations of operating buildings that fall into the zone of influence of underground construction. The subject of the study was the calculated justification of the modern technology of compensatory injection. The relevance of the task is determined by the fact that the choice of the most effective protection technology should be based not only on a comparison of technological precipitation with maximum permissible values, but also on the assessment of the possibility of monitoring and controlling the movements of the foundations of buildings and structures during construction and subsequent operation. The purpose of the study was to compare various methods of protecting the foundations of existing buildings and structures and justify the selection of the most effective of them for further implementation and dissemination in the design and construction of urban underground structures. Materials and methods. On the basis of the survey data of the operated building falling into the impact zone of excavation of the pit for the construction of the installation and shield chamber of the subway, the parameters of the stress-strain state of its foundations are studied by mathematical modeling. The problem was solved by the finite element method based on the software and computer complex Z_Soil v.18.24. Results. Based on the analysis of the results of the examination of the administrative building using the finite element method, a change in the parameters of the stress-strain state of the foundations was modeled with various technologies for strengthening it. In the course of solving the geotechnical problem, it was found that the minimum impact on the foundations of the building during the construction of the pit was obtained in the method of compensatory injection. The system of criteria for making a decision on choosing an effective way to ensure the suitability of buildings in the underground construction zone for operation is substantiated. Conclusions. The results of this work can be used to justify the choice of technology for prevention and control of excess deformations of foundations. The function for calculating the volume of injected material in the Z_Soil software and computer complex can be used to justify the consumption of materials and the economic efficiency of the technological solution.


2020 ◽  
Vol 2020 ◽  
pp. 1-14
Author(s):  
Hua-feng Shan ◽  
Shao-heng He ◽  
Yu-hua Lu ◽  
Wei-jian Jiang

Excavation beneath existing buildings may cause the superstructure to tilt and crack, which seriously affects the normal use of the superstructure. Due to the new working conditions of excavation beneath existing buildings, related case reports are rare and limited. In the case of No. 3 section basement construction project of Ganshuixiang, we monitored the excavation construction by burying test instruments at the designated location. Afterwards, Plaxis 3D finite element software was used to establish an underpinning pile-cap-excavation model, which can analyze the influence of different pile cutting sequences on the bearing behavior of new basement structural pillars. By comparing the in situ measurement data with the finite element model, it can be concluded that when the excavation depth rises, the axial force of the underpinning pile gradually increases, and the pile skin friction is slowly exerted from top to bottom. Different cutting sequences will influence the bearing behavior of the structural pillar. Moreover, the pile cutting process also significantly impacts its bearing behavior and the settlement behavior of the superstructure. Compared with the clockwise pile cutting sequence, the symmetrical pile cutting is more advantageous. In the whole process of the storey adding and reconstruction, the superstructure settlement is related to the working condition of digging and adding layers. In the stage from soil excavation to the concrete curing period of the structural pillar, it increases slowly with time and tends to be stable in the concrete curing period. However, in the pile cutting stage, the superstructure settlement increases sharply, and after pile cutting, it becomes stable.


2014 ◽  
Vol 501-504 ◽  
pp. 286-290
Author(s):  
Shan Shan Xu ◽  
Qiu Sheng Gao

Construction site-monitoring on adjacent existing building’s pile foundation,using ANSYS finite element software to simulate the deformation of adjacent pile foundation when foundation pit excavation. Combined with measured data to analyze the interaction of foundation pit excavation and adjacent existing building’s pile foundation and draw the conclusion that the measured settleme-nt of pit’s adjacent pile is greater than the model’s theoretical value and the pit excavation has certain influence on the pile foun-dation’s vertical displacement of existing buildings.


2013 ◽  
Vol 779-780 ◽  
pp. 1180-1183
Author(s):  
Ke Wu

t constitutes a common problem that deep foundation exerts negative influences on adjacent underground structures. The Chegongmiao subway station is adjacent to the first subway of Shenzhen and Fengshengding shopping street, which is on the planning construction of Shenzhen 11th subway. Based on the finite element method, the paper is investigated to efficiently simulate the effect of the deep foundation on the adjacent underground structures. The engineering measures to reduce the influence of construction are supported for determine the construction plan.


Author(s):  
Della Amelia ◽  
Inda Sumarli ◽  
Ali Iskandar

In a deep excavation construction that adjacent to the existing buildings there is a concern that it will have a bad impact or effect on adjacent buildings.  The effect of deep excavation induced deformation of the existing structures due to ground movements and ground surface settlement behind the wall which can cause a tilt of the building. The objective of this study is to observe the effect of deep excavation (7 storey basement) adjacent to the existing buildings with 7 and 5 storey basement located in South Jakarta. The basement is connected to the basement of the existing building so that the effect of diaphragm wall opening for connecting basement towards the substructures of the existing building is observed. This study was conducted by observing the deformation that occurs in the diaphragm of the existing building, and also observing the internal forces acting on the basement floors slabs of the existing buildings. Observations were made using a three-dimensional finite element program with the most commonly used material model for analysis of deep excavation, The Hardening Soil Model. The analysis was performed with drained conditions with phreatic calculation type and only calculated the static conditions. Results indicate that the deflection that occurs after the final stage of excavation is still within the allowable limit according to the SNI 8460:2017, which is less than 14 centimeters on the diaphragm wall of the existing buildings. Keywords: Deep Excavation; Connecting Basement; Diaphragm Wall; Hardening Soil; Finite Element AbstrakPada suatu konstruksi galian dalam yang berdekatan dengan suatu bangunan lain dikhawatirkan akan memberikan dampak atau efek yang buruk terhadap bangunan di sekitarnya. Efek dari galian dalam tersebut menyebabkan terjadinya deformasi pada struktur dari bangunan di sekitarnya akibat dari pergerakan tanah dan penurunan permukaan tanah di belakang dinding yang dapat menyebabkan bangunan tersebut menjadi miring. Tujuan dari penelitian ini yaitu untuk mengamati pengaruh pekerjaan galian dalam (basement dengan 7 lantai) yang berdekatan dengan bangunan sekitar dengan basement 5 lantai dan 7 lantai yang berlokasi di Jakarta Selatan. Basement yang dimodelkan terkoneksi dengan basement dari bangunan eksisting sehingga diamati pengaruh bukaan dinding diafragma untuk connecting basement terhadap struktur bawah bangunan eksisting. Penelitian ini dilakukan dengan melihat deformasi yang terjadi pada dinding diafragma dari bangunan eksisting, dan juga mengamati gaya-gaya dalam yang bekerja pada pelat lantai basement dari bangunan eksisting. Pengamatan dilakukan dengan menggunakan program elemen hingga tiga dimensi dengan model material yang paling umum digunakan yaitu Hardening Soil untuk analisis galian dalam. Analisis dilakukan dengan kondisi drained dengan tipe kalkulasi phreatic serta hanya memperhitungkan keadaan static. Hasil menunjukkan bahwa defleksi yang terjadi setelah tahapan terakhir pekerjaan galian dalam yaitu masih dalam batas yang diijinkan menurut SNI 8460:2017 yaitu dibawah dari 14 cm pada dinding diafragma bangunan eksisting. 


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