# Prediction of Ground Deformation during Pipe-Jacking Considering Multiple Factors
## 1 Introduction  
During this period of rapid urbanization in China, many underground facilities are being constructed, e.g., underground commercial centers [1; 2; 3; 4; 5; 6], metro systems [7; 8; 9; 10; 11; 12; 13; 14; 15], pipelines for water supply [16; 17; 18; 19; 20; 21; 22; 23], and communication cables [24; 25; 26; 27; 28]. Pipe-jacking, as a trenchless construction technology, has been widely used in these construction projects [29; 30]. With matured operation technology and high level of automation, pipe-jacking is suitable for application in various geological conditions, such as silty clay, sandy silt and sandy soil [31; 32; 33; 34; 35; 36; 37; 38]. However, the geological characteristics of problematic materials such as soft clay is complex [39; 40; 41]. During tunneling in soft clay conditions, the jacking process will cause the deformation of surrounding soil, then result in the displacement of nearby buildings [52; 53]. To mitigate the environmental disturbance, the prediction of ground deformation is important in pipe-jacking construction.  
The essential factor of ground deformation is the ground movement induced by pipe-jacking [54]. Many theoretical analyses have been conducted to study the ground movement. Previous research indicated that ground deformations are influenced by the following factors: (i) ground loss; (ii) pressureon excavation face (namely bulkhead additive thrust); (iii) lateral friction on jacking machine; and (iv) grouting process, etc. [55; 56; 57]. Due to similar procedures, researchers often prefer the option of shield tunneling for the ground deformation induced by pipe-jacking. [PERSON] [58] assumed that the ground movement is uniform. The consolidation condition of stratum is considered to be undrained. Subsequently, the ground loss was used to calculate the ground deformation in three dimensions. [PERSON] and [PERSON] [59] improved [PERSON]'s calculation of ground deformation by considering the radial ground movement as oval-shaped. To analyze the longitudinal ground movement, [PERSON] et al. [60] used [PERSON]'s solution to calculate ground movement induced by the bulkhead additive thrust and lateral friction during pipe-jacking. However, the grouting process as an important process during pipe-jacking has not been studied in the aforementioned methods [61]. Considering the grouting process, the lateral friction between pipe segments and surrounding soils will be reduced due to the existence of slurry [17]. Furthermore, the grouting pressure will apply additional stresses on the surrounding soils and result in ground movement [62]. In addition, numerical methods are widely used to simulate the ground movement [63]. [PERSON] et al. [64] found that performance of mud slurry plays an important role in the pushing process and that suitable slurry pressure is proved to be necessary for the stability of surrounding soils by numerical simulation [65; 66].  
This paper proposes a new approach to predict ground deformation induced by pipe-jacking construction. The grouting process is considered to be a new factor for the ground movement during pipe-jacking. To achieve this goal, [PERSON]'s solution will be used to calculate the ground movement induced by the grouting process. A case study of pipe-jacking construction will be analyzed to verify the proposed method.