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CN-121977403-A - Construction method for vibration isolation by freezing method

CN121977403ACN 121977403 ACN121977403 ACN 121977403ACN-121977403-A

Abstract

A construction method for vibration isolation by a freezing method comprises the following steps of S1, forming an underground freezing barrier in foundation soil between a preset collapse area of a building to be blasted and a protected building in an artificial refrigeration mode, and S2, after the integrity and strength of the freezing barrier are confirmed, performing directional blasting on the building to be blasted. The frozen ice-soil mixture has the characteristics of high strength and high damping, can effectively reflect, scatter and absorb vibration waves, and has a damping effect obviously superior to that of the traditional damping ditches and the traditional damping dykes. The adaptability is strong, the method is not limited by unfavorable geological conditions such as groundwater and complex stratum, and is especially suitable for working conditions such as soft soil and water-rich stratum where deep trenches are difficult to excavate. The construction process is pollution-free, the barrier is naturally melted after blasting, the land is restored to the original state, no building rubbish is generated, and the influence on the ecological environment of the field is very small.

Inventors

  • WANG HONGCHUN
  • MA HONGHAO
  • Shao xianfeng
  • SHI WEI
  • MA LEI
  • WANG LUQING
  • WU MINGCHUN
  • LIU YONG
  • Han Junshuai
  • WANG PENG
  • SONG HUASONG
  • Lei Qingkun

Assignees

  • 中国科学技术大学
  • 国网安徽省电力有限公司
  • 国网安徽省电力有限公司建设分公司
  • 安徽送变电工程有限公司

Dates

Publication Date
20260505
Application Date
20260211

Claims (9)

  1. 1. The construction method for vibration isolation by a freezing method is characterized by comprising the following steps of: S1, forming an underground freezing barrier in foundation soil between a preset collapse area of a building to be blasted and a protected building in an artificial refrigeration mode; s2, after the integrity and strength of the freezing barrier are confirmed, performing directional blasting on the building to be blasted.
  2. 2. The construction method according to claim 1, wherein in step S1, the construction method of the frozen barrier comprises the steps of: a1, drilling holes at preset positions and installing freezing pipes; and a2, conveying cooling liquid into the freezing pipes through a refrigerating device to freeze surrounding soil, controlling the freezing interval and freezing time of the freezing pipes, and enabling the frozen holes to form freezing wall intersecting circles to form a continuous freezing barrier.
  3. 3. The construction method according to claim 2, wherein the cooling liquid is low-temperature brine or liquid nitrogen.
  4. 4. The construction method according to claim 2, wherein the freezing barrier is in the shape of a vertical wall, an inclined wall, or a stepped wall.
  5. 5. The construction method according to claim 1, characterized by further comprising, before step S1: S0, determining the value of the freezing barrier according to parameters of the building to be blasted, the collapse direction, the site geological conditions and the position of the protected building.
  6. 6. The method of construction according to claim 5, wherein the value of the frozen barrier comprises a geometric dimension; the geometric dimension determining method comprises the steps of obtaining shear wave velocity of a site soil body By empirical formula Calculating Rayleigh wave speed According to Exciting a foundation soil body to vibrate by an impact load when a building to be blasted collapses and touches the ground; Calculating Rayleigh wavelength , Setting the depth H of the freezing barrier to be larger than the Rayleigh wavelength Width W is between 1 2 Thickness of (thickness of) And is not less than 1 meter, wherein P is impact load, and sigma is allowable stress of soil body.
  7. 7. The construction method according to claim 5, wherein the value of the freezing barrier further includes a spatial position including a horizontal position between the predetermined collapse area and the protected object, the horizontal position being not less than 0.5 to 0.7 times the height of the blasted building, and the distance from the protected object being maintained at a distance of 5 to 10m or more.
  8. 8. The method of construction of claim 5, wherein the value of the frozen barrier further comprises the frozen process parameters: the hole spacing between the holes is about 0.8-1.2 m, and when the design thickness is more than 1.5 m, double calandria or multiple rows of freezing pipes are needed; the double rows of pipes are arranged in a quincuncial shape, and the row pitch is 0.8-1.0 times of the hole pitch.
  9. 9. The construction method according to claim 1, further comprising, after step S2: And S3, stopping refrigerating after blasting is completed, so that the freezing barrier is naturally melted, and the foundation soil body is restored to the original state.

Description

Construction method for vibration isolation by freezing method Technical Field The invention relates to the technical field of blasting, in particular to a construction method for vibration isolation by a freezing method. Background In urban renovation or industrial reconstruction, directional blasting demolition of tall structures (e.g., concrete stacks, cooling towers, etc.) is often required. During the blasting collapse, huge impact energy acts on the ground, and intense seismic waves (including bulk waves and surface waves) are generated. The vibration waves can be transmitted to the periphery through foundation soil, and damage to adjacent civil houses, pipelines, traffic facilities and the like is caused to different degrees, such as wall cracking, structural damage and the like, so that safety and economic disputes are caused. At present, the conventional damping methods are mainly divided into two types, namely, a damping channel is dug between a blasting body and a protected body, and damping is performed by cutting off the propagation path of a wave. However, in the areas with abundant soft soil layers or underground water, the deep ditches are excavated to easily cause the problems of slope collapse, water seepage and the like, the construction difficulty is high, the cost is high and the safety is poor. Secondly, a buffer soil dike or a stacking sand bag is arranged in front of the protected body, but the method occupies large space, has limited damping effect and has no obvious damping effect on high-strength impact energy. Disclosure of Invention The invention aims to overcome the defects of the prior art, and the technology utilizes a manual freezing method to quickly form a continuous and compact freezing barrier wall in foundation soil between a blasting collapse area and a protected building, and the barrier can effectively dissipate, reflect and absorb earthquake wave energy generated by blasting impact, thereby achieving an excellent vibration isolation effect. The aim of the invention can be achieved by the following technical scheme: A construction method for vibration isolation by a freezing method comprises the following steps: S1, forming an underground freezing barrier in foundation soil between a preset collapse area of a building to be blasted and a protected building in an artificial refrigeration mode; s2, after the integrity and strength of the freezing barrier are confirmed, performing directional blasting on the building to be blasted. In a further aspect of the present invention, in step S1, the construction method of the frozen barrier includes the steps of: a1, drilling holes at preset positions and installing freezing pipes; and a2, conveying cooling liquid into the freezing pipes through a refrigerating device to freeze surrounding soil, controlling the freezing interval and freezing time of the freezing pipes, and enabling the frozen holes to form freezing wall intersecting circles to form a continuous freezing barrier. As a further scheme of the invention, the cooling liquid is low-temperature brine or liquid nitrogen. As a further proposal of the invention, the freezing barrier is in the shape of a vertical wall, an inclined wall or a stepped wall. As a further aspect of the present invention, before step S1, the method further includes: S0, determining the value of the freezing barrier according to parameters of the building to be blasted, the collapse direction, the site geological conditions and the position of the protected building. And the exploration and design stage is to determine the position, the geometric dimension (thickness, width and depth) and the freezing construction period of the freezing barrier according to the structural parameters, the collapse direction, the site geological hydrologic condition and the position and structural characteristics of the protected building of the structure to be exploded and dismantled. Shear wave velocity of common soilObtaining the mixture in an empirical range (soft clay, filled soil: hard clay of 100-200 m/s, sandy soil: strong weathered rock of 200-400 m/s, complete rock of 400-600 m/s: >600 m/s)。 The freezing period is more practical and determined by freezing facilities. As a further aspect of the invention, the value of the freezing barrier comprises a geometric dimension; the geometric dimension determining method comprises the steps of obtaining shear wave velocity of a site soil body By empirical formulaCalculating Rayleigh wave speedAccording toCalculating Rayleigh wavelength; Setting the depth H of the freezing barrier to be larger than the Rayleigh wavelengthWidth W is between 12Thickness of (thickness of)And is not less than 1 meter, wherein P is impact load, sigma is allowable stress of soil body,And exciting the foundation soil body to vibrate by the impact load when the building to be blasted collapses to touch the ground. The numerical value of the freezing barrier further comprises a space posit