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CN-121993214-A - Construction method for butt joint of unequal-diameter shield penetrating sand layer in long distance in underwater soil layer

CN121993214ACN 121993214 ACN121993214 ACN 121993214ACN-121993214-A

Abstract

The invention discloses a construction method for butting unequal-diameter shields penetrating sand layers in long distances on underwater soil layers, which comprises the steps of 1, tunneling a large-diameter normal-pressure cutter head shield and a small-diameter normal-pressure cutter head shield in opposite directions, 2, reinforcing the periphery of the large-diameter normal-pressure cutter head shield and the stratum in front of the cutter head shield in a butting area in a freezing mode, 3, reinforcing the periphery of the small-diameter normal-pressure cutter head shield and the stratum in front of the cutter head shield in a freezing mode at a distance of 1m to 2m from the large-diameter normal-pressure cutter head shield to form a complete freezing reinforcing area, 4, tunneling the small-diameter normal-cutter head shield until the distance from the large-diameter normal-pressure cutter head shield is smaller than 10 cm, retracting the large-diameter normal-pressure cutter head shield and suspending tunneling completely after the large-diameter normal-pressure cutter head shield is tightly attached, 5, dismantling equipment in the two shields, and 6, constructing a connecting structure in the butting area. The invention solves the technical problem of frequent cutter replacement of the small-diameter conventional cutterhead shield in the construction of the unequal-diameter shield tunnel penetrating through the sand layer in a long distance.

Inventors

  • ZHOU YU
  • GU JUNWEN
  • YAO JIAN
  • ZHANG YUHANG
  • CHEN GANG
  • WANG WENYUAN
  • Zhao Danming

Assignees

  • 上海市城市建设设计研究总院（集团）有限公司

Dates

Publication Date
20260508
Application Date
20260317

Claims (7)

  1. 1. The construction method for butting the unequal-diameter shield penetrating through the sand layer in a long distance on an underwater soil layer is characterized by comprising a larger-diameter section penetrating through the water-rich sand layer or the stratum for more than 1km in a long distance and tunneling by adopting a large-diameter normal-pressure cutterhead shield (1), a smaller-diameter section penetrating through the soft soil layer and tunneling by adopting a small-diameter conventional cutterhead shield (2), and a butting area between the larger-diameter section and the smaller-diameter section; the large-diameter normal-pressure cutterhead shield and the small-diameter conventional cutterhead shield are coaxially butted; the construction steps are as follows: step 1, tunneling the large-diameter normal-pressure cutterhead shield (1) and the small-diameter conventional cutterhead (2) in opposite directions according to a designed route, wherein the large-diameter normal-pressure cutterhead shield (1) reaches the butt joint area in advance of the small-diameter conventional cutterhead shield (2); Step 2, after the large-diameter normal-pressure cutterhead shield (1) reaches the butt joint area, suspending tunneling, and reinforcing stratum around the large-diameter normal-pressure cutterhead shield (1) and in front of the cutterhead by adopting a freezing mode through a corresponding large shield radiation freezing pipe (3-1); Step 3, after the small-diameter conventional cutterhead shield (2) approaches to a distance of 1m to 2m from the large-diameter normal-pressure cutterhead shield (1), suspending tunneling, and reinforcing stratum around the small-diameter conventional cutterhead shield (2) and in front of the cutterhead by adopting a freezing mode through a corresponding small shield radiation freezing pipe (3-2), so as to form a complete freezing reinforcing area (4) in the stratum of the butt joint area to be constructed; Step 4, tunneling the small-diameter conventional cutterhead shield (2) at a speed of 2mm/min to 10mm/min after reinforcement is completed until the distance from the large-diameter normal-pressure cutterhead shield (1) is smaller than 10 cm, retracting the large-diameter normal-pressure cutterhead shield (1) at a speed smaller than the advancing speed of the small-diameter conventional cutterhead shield (2), and suspending tunneling after the cutterheads of the large-diameter normal-pressure cutterhead shield (1) and the small-diameter conventional cutterhead shield (2) are tightly attached; Step 5, gradually dismantling equipment in the shield shells of the large-diameter normal-pressure cutterhead shield (1) and the small-diameter normal-pressure cutterhead shield (2) under the condition that shield tails between the large-diameter normal-pressure cutterhead shield (1) and the small-diameter normal-pressure cutterhead shield (2) and corresponding shield segments are reserved; and 6, constructing a connection structure (5-3) with a gradual change section in the butt joint area by adopting an integral cast-in-situ process.
  2. 2. The construction method for the unequal-diameter shield crossing the sand layer for a long distance to butt joint in the underwater soil layer according to claim 1 is characterized in that the large-diameter normal-pressure cutterhead shield (1) and the small-diameter normal-pressure cutterhead shield (2) are both provided with a freezing cutterhead and a double-layer shield shell.
  3. 3. The construction method of the unequal diameter shield crossing the sand layer for a long distance in the butt joint of the underwater soil layer according to claim 1 is characterized in that in the step 2 and the step 3, a core drilling method or an advanced geological prediction method is adopted to detect the reinforcing effect of the stratum around the large diameter normal pressure cutterhead shield (1) and in front of the cutterhead and the reinforcing effect of the stratum around the small diameter normal cutterhead shield (2) and in front of the cutterhead.
  4. 4. The construction method of the unequal diameter shield penetrating through the sand layer in the long distance under water soil layer butt joint according to claim 1 is characterized in that when the step 4 is executed, secondary grouting is carried out after the wall, and the dense state is ensured between the shield shells of the large diameter normal pressure cutterhead shield (1) and the small diameter normal cutterhead shield (2) and the surrounding soil body.
  5. 5. The construction method for butt joint of unequal diameter shields penetrating sand layers in long distances in underwater soil layers according to claim 1, wherein in the step 5, a section of reinforced concrete segments (5-1, 5-2) of the larger diameter section and the smaller diameter section closest to the butt joint area are fixed between shield shells of the corresponding large diameter normal pressure cutter head shield (1) or the corresponding small diameter normal pressure cutter head shield (2) respectively by welding a backstop steel plate.
  6. 6. The construction method for butt joint of unequal diameter shields penetrating sand layers in long distances under water, according to claim 1, wherein when step 5 is executed, long steel plate drawknots are welded on the inner surfaces of the segments of the larger diameter section and/or the smaller diameter section.
  7. 7. The construction method for butt joint of unequal diameter shields penetrating through sand layers in long distances on underwater soil layers according to claim 1 is characterized by comprising the steps of detecting whether cavities exist outside shield shells of a large-diameter normal-pressure cutterhead shield (1) and a small-diameter conventional cutterhead shield (2) or not before executing step 6, grouting and filling each cavity if the cavities exist, and spraying anticorrosive waterproof paint such as polyurea and the like in the shield shells.

Description

Construction method for butt joint of unequal-diameter shield penetrating sand layer in long distance in underwater soil layer Technical Field The invention relates to the technical field of shield tunnel construction, in particular to a construction method for butt joint of unequal-diameter shields penetrating sand layers in long distances in underwater soil layers. Background When the existing small-diameter conventional cutter head shield passes through broad water systems such as Yangtze river and the like or composite stratum in south China, a tunnel often partially passes through a dense sand layer or rock stratum with high quartz content. When the river flushing depth is large, the tunnel burial depth needs to be deepened, so that the small-diameter underwater shield needs to locally penetrate through a composite stratum or a high-quartz-content compact sand layer in a long distance, and the cutter is seriously worn by abrasive minerals such as quartz, so that frequent cutter replacement is needed. If the shield tunnel of the Yangtze river of the ZhongRudong line is in tunneling, the cutter is replaced three times. At present, when the shield is used for replacing the cutter of the underwater loose and strong-permeability and high-water pressure stratum, two modes of normal-pressure cutter disc cutter replacement and under-pressure cabin opening cutter replacement can be generally adopted: 1. And in the cutter heads of the hollow spokes and the replaceable cutter cylinder, workers enter the hollow spokes to finish cutter replacement under normal pressure, the workers do not need to press during operation, the cutter replacement period is short, the construction efficiency is high, and the cutter replacement risk is low. At present, the normal pressure cutter replacing technology is mature in application on shield machines with diameters exceeding 11 m. However, the small-diameter conventional cutterhead shield has operation risks caused by space limitation, narrow cabin operation space, easiness in causing mechanical collision, limited movable radius of a cutter changing mechanical arm and the like, and the normal-pressure cutterhead structure is difficult to apply. At present, the world minimum diameter normal pressure cutterhead shield is successfully applied to a middle Russian east line Yangtze river tunnel, the shield diameter is 7.95m, 10.2km is tunneled at the bottom of the Yangtze river, and three normal pressure tool changing is implemented. For the small-diameter conventional cutterhead shield tunnel (phi <6 m), when adopting the normal-pressure cutterhead structure, the shield diameter is required to be increased, the investment is increased, and the economical efficiency is poor. 2. And (3) under-pressure cabin opening tool changing, namely on the premise of ensuring the stability of an excavated surface, an operator enters a pressure cabin to maintain and change the tool under the air pressure environment. In order to ensure the stability of the excavation surface, a layer of mud film (mud permeation film) with good air tightness is formed at the excavation surface of the stratum, so that the air pressure in the pressure cabin balances the water and soil pressure in the stratum. There are also disclosures that compressed air pressure cabin-entering tool changing, mixed gas pressure cabin-entering tool changing, saturated gas cabin-entering tool changing and the like can be adopted during underwater loose strong-permeability and high-water pressure stratum tool changing. Such as Nanjing latitude three-way tunnel, istein Bose Prussian channel tunnel, and submarine tunnel with angles from Tunmen to lie. However, the above scheme has the following problems: (1) Under the conditions of loose and strong permeability under water and high water pressure, the maintenance of a mud film and the pressure maintaining of air pressure are difficult, and a large risk is brought to the under-pressure cabin opening tool changing. (2) When ultrahigh pressure cabin entering operation (water pressure is more than 0.6 MPa) is adopted, a saturated diving cabin opening tool changing technology is often adopted, operators always live in the ground high-pressure living cabin during cabin opening operation, the high-pressure shuttle cabin is in butt joint with the shield machine air pressure cabin, the operators enter the pressure cabin to work, and the operators return to the ground high-pressure living cabin through the high-pressure shuttle cabin after one operation is completed, so that the operation is repeated until one decompression cabin outlet is carried out after the work is completed. When the ultra-high pressure cabin opening tool changing is carried out on the small-diameter conventional cutterhead shield, the high-pressure shuttle cabin is connected with the shield robot gate cabin, and because of space limitation, the diameter of the shield is possibly increased or a frame system of part of the shie