Research on rock breaking mechanism and load characteristics of TBM cutter based on discrete element method

Abstract

Tunnel boring machine (TBM) is a large-scale tunnel engineering equipment, which has unparalleled advantages in safety and work efficiency. The cutter is subjected to complex and variable random impact loads, resulting in damage to bearings, cutter rings, and cutter shafts. Therefore, based on the discrete element simulation platform and experiment, this paper established the cutter rock simulation model based on the experimental data, and analyzed the rock breaking process, cutter load magnitude, and variation law. The research results show that when the cutter pole diameter decreases from 200 mm, 100 mm, and 0 mm in sequence, the rolling force increases accordingly, and the maximum increase of the rolling force is 56%. Meanwhile the lateral force decreases and the maximum average decrease value is 26%. Moreover, the rolling force showed a downward trend with the increase of the cutter spacing. When the cutter spacing is increased from 80 mm to 120 mm, the average rolling force decreases by 51%, and the maximum value rises slightly, increasing by 2%. And, the lateral force tends to increase, with an increase of 17% and the maximum lateral force value increase was 29%. The results can provide load input reference for TBM cutter layout, cutterhead structure design, and performance evaluation.

Prediction method of TBM tunnel surrounding rock classification based on LSTM-SVM

“…This method is called sliding window method, where the number of steps in the past time is called window width t. The width of the sliding window is the basis of prediction model. The five characteristic parameters total thrust, cutterhead torque, shoe support pressure, cutterhead rotate speed, and advance speed are expressed as x (1) , x (2) , x (3) , x (4) , x (5) , respectively. Taking the total thrust x (1) as an example, when the sequence is x (1) 1 , x (1) 2 , Á Á Á , x (1) 34560 n o , assume the training window width t = 5, and the training samples for the LSTM network predictor f are formed as follows:…”

“…TBM is a kind of large-scale digital tunneling equipment, which is widely used in subways, water conservancy, highways, railways tunnel construction. [1][2][3] In the process of TBM construction, the type of surrounding rock is the key index of surrounding rock stability evaluation and tunneling performance prediction. 4,5 Predicting the surrounding rock classes accurately within a short distance is very helpful for the workers to formulate corresponding supporting measures in time.…”

Rapid assembly bolt connection design method for TBM disc cutter box based on AHP

“…Yang et al 19 In accordance with the construction requirements and geological conditions of TBM, a hybrid fuzzy comprehensive evaluation method was employed, utilizing both qualitative and quantitative indicators to select a cutter holder that meets the design specifications. Entacher et al [20][21][22][23] Load and vibration analyses were conducted on the cutting tools and tool holders, assisting in the TBM design and extending the lifespan of both the cutting tools and their holders. Huo et al 24,25 A dynamic model of the TBM cutting tool system and a predictive model for tool loads were established.…”