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CN-121980640-A - Foam light soil roadbed multi-element load shedding deformation regulation and control method based on structural stress control and roadbed structure

CN121980640ACN 121980640 ACN121980640 ACN 121980640ACN-121980640-A

Abstract

The invention relates to the technical field of road engineering and provides a foam light soil roadbed multi-element load shedding deformation regulation and control method based on structural stress control and a roadbed structure, wherein the method comprises the steps of selecting soil bodies with different sections and different depths of a construction road section for drilling and sampling; the method comprises the steps of carrying out a one-dimensional consolidation compression test on undisturbed soil to determine the yield stress of the soil structure, preferentially considering the deformation regulation and control of the foam light soil light filler, and selecting the vacuum preloading and the foam light soil deformation regulation and control if the process cannot meet the condition that the upper load is smaller than the yield stress of the soil structure. In the extreme case (the foundation is extremely weak in structural performance or the upper design load is larger), the deformation regulation and control of the large-diameter pipe embedded in the foam lightweight soil are combined by vacuum preloading. The invention is based on the structural stress control multi-element load-shedding deformation regulation thought, can ensure that the load borne by the foundation is always lower than the structural yield stress in the roadbed construction process, maintains the structural integrity of the soil body to the maximum extent, effectively controls the deformation of the foundation and improves the engineering stability.

Inventors

  • LIU YANG
  • YU PENGQIANG
  • WU KEJIA
  • LI DONGSHENG
  • CHEN BINGXU

Assignees

  • 北京科技大学

Dates

Publication Date
20260505
Application Date
20251223

Claims (10)

  1. 1. The foam light soil roadbed multi-element load shedding deformation regulation and control method based on the structural stress control is characterized by comprising the following steps of: S1, selecting soil bodies with different sections and different depths in a construction road section for drilling and sampling, and measuring basic mechanical parameters of the soil bodies through a test; s2, carrying out a one-dimensional consolidation compression test on the obtained undisturbed soil, drawing a compression curve based on test data and the basic mechanical parameters, and determining the yield stress of the soil body structure according to the inflection point of the compression curve; s3, selecting and implementing a load shedding deformation regulation scheme based on the structural yield stress and the additional stress generated by the design load determined in the step S2, wherein the regulation scheme comprises the following steps: The method comprises the following steps of (1) regulating and controlling the deformation of foam lightweight soil, wherein foam lightweight soil is adopted as lightweight filler in embankment filling so as to reduce the overburden load and control the additional stress below the structural yield stress; The scheme (2) is that the vacuum preloading and foam lightweight soil deformation regulation and control are combined, wherein when the scheme (1) cannot meet the condition that the additional stress is smaller than the structural yield stress, the foundation is subjected to vacuum preloading treatment before embankment filling, and then foam lightweight soil filling is carried out; and (3) regulating and controlling deformation of the large-diameter pipe embedded in the vacuum preloading and foam lightweight soil, wherein when the additional stress is still not smaller than the structural yield stress in the scheme (2), the large-diameter hollow pipe is embedded in the foam lightweight soil while the vacuum preloading treatment and the foam lightweight soil filling are carried out.
  2. 2. The method according to claim 1, wherein the basic mechanical parameters in step S1 include initial void ratio, compression consolidation coefficient, cohesion and internal friction angle.
  3. 3. The method of claim 1, wherein the one-dimensional consolidation compression test in step S2 is a load-unload-reload process, and the load path is 12.5- > 25- > 50- > 75- > 100- > 150- > 200- > 150- > 100- > 75- > 50- > 25- > 50- > 75- > 100- > 150- > 200- > 300- > 400 kPa.
  4. 4. The method according to claim 1, wherein the compression curve in step S2 is a pore ratio-pressure curve on a double logarithmic scale.
  5. 5. The method according to claim 2, wherein the method further comprises a scheme preselection step before the step S3, wherein the structural strength of the foundation is pre-estimated according to the basic mechanical parameters of the soil body measured in the step S1 and the structural yield stress determined in the step S2 by combining the design load of the upper embankment; wherein if the pre-evaluation indicates that the structural yield stress is lower than the design load, the scheme (1) is preferentially adopted; when the structural yield stress is still lower than the design load after rechecking and evaluating in the scheme (1), adopting the scheme (2) or the scheme (3); for extremely soft foundations with large thickness and high water content or major engineering with design load far greater than structural yield stress, the adoption of the scheme (3) is directly determined.
  6. 6. The method according to claim 1, wherein in the step S3, the foam lightweight soil is filled on a sand cushion layer, the sand cushion layer is laid on an original roadbed, the vacuum pre-pressing treatment is performed by using a drainage plate to drain water, a cross section pipe is used for monitoring the vertical sedimentation of soil mass on the whole continuous section, and the large-diameter hollow pipe is a low-density hollow pipe.
  7. 7. The method according to claim 1, wherein the soil pressure and settlement amount of the roadbed are monitored in real time during and after any one of the regulation and control schemes is implemented in step S3, and the deformation control effect is evaluated based on the monitored data, and if necessary, the construction parameters or the reinforcement measures are dynamically adjusted.
  8. 8. The method according to claim 1, wherein the foamed lightweight soil has a wet bulk weight of 5-12 kN/m 3 , an unconfined compressive strength of not less than 0.5 MPa for 28 days, a vacuum degree of not less than 80 kPa for the vacuum preloading treatment, and a preloading period determined according to a consolidation degree requirement.
  9. 9. The method of claim 6, wherein the drainage plates are arranged in a regular triangle, the distance between the drainage plates is 1.5m, the cross section pipes are arranged across the whole roadbed, the large-diameter hollow pipes are corrugated steel pipes and are arranged perpendicular to the central line of the roadbed, and the distance between the pipes is 2.0-3.0 m.
  10. 10. A roadbed structure which is characterized by being constructed by adopting the foam lightweight soil roadbed multi-element load-shedding deformation regulation and control method based on structural stress control according to any one of claims 1 to 9.

Description

Foam light soil roadbed multi-element load shedding deformation regulation and control method based on structural stress control and roadbed structure Technical Field The invention relates to the technical field of road engineering, in particular to a method for constructing a roadbed on a soft soil foundation, and particularly relates to a foam light soil roadbed multi-element load-shedding deformation regulation and control method based on structural stress control and a roadbed structure. Background When road construction is carried out in coastal areas, river networks and other areas, deep soft soil foundations are often encountered. The foundation has the characteristics of high water content, high compressibility, low bearing capacity, poor water permeability and the like, and can generate extremely large sedimentation and uneven sedimentation under the load action of the embankment, thereby seriously affecting the construction safety and long-term operation performance of the road. Thus, soft soil foundation treatment is a key element of such engineering. The traditional soft foundation treatment method, such as a preloading method, is to apply temporary load exceeding the design load to accelerate the consolidation settlement of the foundation, and then to carry out road construction after the settlement is stable. Although this method is widely used, the core is "stable with sedimentation", and the structural nature of soft soil itself is not considered. Soft soil develops a certain structural strength, i.e. "structural yield stress", during the deposition process. When the external load exceeds the critical value, the soil structure is irreversibly damaged, so that the strength is suddenly reduced and the compressibility is greatly increased, and sudden and uncontrollable large deformation or instability can be caused. In addition, the traditional method usually adopts conventional fillers (such as earthwork) to carry out high filling, and the dead weight load is large. In a structural soft soil area, the large load is extremely easy to break through the yield stress of the soil structure, and excessive post-construction sedimentation and differential sedimentation are induced. In the prior art, although light materials such as foam light soil and the like are started to lighten loads or vacuum pre-pressing is adopted to strengthen the foundation, the technologies are often used in isolation or simple superposition, and a unified theoretical frame is lacked for quantitative design and systematic regulation. How to accurately identify the structural yield point of the foundation, and taking the structural yield point as a core, and cooperatively allocating various load shedding and reinforcing technologies to realize the transition from 'passive processing sedimentation' to 'active control stress and deformation' is a technical problem to be solved at present. Disclosure of Invention The invention aims to overcome the defects of the prior art and provides a foam light soil roadbed multi-element load-shedding deformation regulation and control method based on structural stress control and a roadbed structure. The method takes the yield stress of the soil structure as a core control threshold value, adopts multiple technologies such as light filler replacement, vacuum preloading combination, composite hollow structure and the like in a grading progressive manner through scientific experiments and evaluations, realizes active and accurate regulation and control of the stress path of the soft soil foundation, and ensures the stability and deformation controllability of the roadbed in construction and operation period. The invention adopts the following technical scheme: On one hand, the invention provides a foam lightweight soil roadbed multi-element load shedding deformation regulation and control method based on structural stress control, which comprises the following steps: S1, selecting soil bodies with different sections and different depths in a construction road section for drilling and sampling, and measuring basic mechanical parameters of the soil bodies through a test; s2, carrying out a one-dimensional consolidation compression test on the obtained undisturbed soil, drawing a compression curve based on test data and the basic mechanical parameters, and determining the yield stress of the soil body structure according to the inflection point of the compression curve; s3, selecting and implementing a load shedding deformation regulation scheme based on the structural yield stress and the additional stress generated by the design load determined in the step S2, wherein the regulation scheme comprises the following steps: The method comprises the following steps of (1) regulating and controlling the deformation of foam lightweight soil, wherein foam lightweight soil is adopted as lightweight filler in embankment filling so as to reduce the overburden load and control the additional stress below