CN108239987B - Method for processing coral sand stratum foundation by adopting large-tonnage vibration rolling - Google Patents

Abstract

The invention relates to a method for processing a coral sand stratum foundation by adopting large-tonnage vibration rolling, which comprises the steps of ground watering- > vibration rolling of a large-tonnage rolling machine- > ground watering- > … - > vibration rolling of the large-tonnage rolling machine until the requirement of times is met- > ground watering- > vibration rolling of a small-tonnage rolling machine- > … - > vibration rolling of the small-tonnage rolling machine until settlement is stable- > foundation detection. The method aims to realize high construction speed, small influence on the surrounding environment and low cost.

Description

Method for processing coral sand stratum foundation by adopting large-tonnage vibration rolling

Technical Field

The invention relates to a method for processing coral sand stratum foundation by adopting large-tonnage vibration rolling, belonging to the technical field of fixed buildings.

Background

With the development of economy, sea reclamation projects are more and more. The sea reclamation project is generally made of local materials and adopts adjacent soil or sand for reclamation. Coral sand, as a material for sea reclamation, has been used in a variety of projects. The physical structure and mechanical properties of coral sand are much different from those of quartz sand. In coral sand stratum, foundation treatment usually adopts dynamic consolidation and vibration-washing foundation treatment method. The two methods have high construction cost and long construction period. In addition, the dynamic compaction processing method and the vibroflotation processing method have great influence on the surrounding environment.

Along with the requirement of the project period is more and more tense, the project cost is more and more strictly controlled. The dynamic compaction processing method and the vibroflotation processing method can not meet the requirements of engineering.

Disclosure of Invention

The invention provides a method for processing coral sand stratum foundation by adopting large-tonnage vibration rolling aiming at the prior art, and aims to realize high construction speed, small influence on the surrounding environment and low manufacturing cost.

The purpose of the invention is realized by the following technical scheme:

the method for processing the coral sand stratum foundation by adopting large-tonnage vibration rolling is suitable for sea areas with seawater depth not greater than 8 meters, and is characterized in that: the method comprises the following steps:

step one, adopting a hydraulic fill construction method to hydraulic fill coral sand to a depth above sea level and more than 1.5 m;

step two, standing the coral sand pile subjected to blow filling for not less than 1 month;

step three, spraying seawater on the upper surface of the coral sand pile, spraying water in an amount which can cause local water accumulation, and rolling after spraying water for 20 minutes;

step four, performing vibration rolling on the upper part of the coral sand pile subjected to blow filling by adopting a large-tonnage rolling machine, wherein the tonnage of the large-tonnage rolling machine is not less than 36 tons, the vibration frequency is 28 Hz-31 Hz, the line passing speed is not more than 5KM/h, and the rolling is performed for 4 times;

step five, repeating the step three and the step four for 8 times;

step six, spraying seawater on the upper surface of the coral sand pile, spraying water in an amount which can cause local water accumulation, and rolling after spraying water for 20 minutes;

seventhly, performing vibration rolling on the upper part of the coral sand pile by adopting a 26-ton vibration rolling machine, wherein the vibration frequency is 27 Hz-31 Hz, the line passing speed is not more than 5KM/h, and rolling for 4 times;

step eight, repeating the step six and the step seven until the sedimentation is stable;

and step nine, foundation detection, including dynamic sounding detection, dry density detection, static load test detection, soil foundation reaction modulus detection and California bearing ratio detection.

The vibration rolling is generally used for layered backfilling, the technical scheme of the invention is based on a certain coral sand blowing and filling project, large-tonnage vibration rolling foundation treatment method research is carried out, and a suitable method for vibration rolling treatment is obtained through field test, and the method has the following characteristics:

1. directly carrying out vibration rolling treatment on the top of the coral sand pile after blow filling without adopting layering rolling treatment;

2. considering the settlement of the coral sand pile after the hydraulic filling under the dead weight, standing for 1 month;

3. on-site tests show that the settlement of the coral sand after the seawater is sprinkled is greater than that of the coral sand without the seawater during vibration rolling, and the coral sand has good permeability, so that the coral sand needs to be subjected to vibration rolling treatment after the seawater is sprinkled for 20 minutes;

4. the tonnage of the vibration rolling equipment is selected, and 36 tons of equipment with the maximum tonnage which can be purchased in the market are selected;

when 36 tons of vibration rolling are carried out, due to the fact that the influence capacity of vibration rolling equipment is strong, during rolling construction, the settlement of the construction process is not easy to stabilize. And finally, rolling by adopting a 26-ton vibration rolling machine, so that the coral sand on the surface layer can be compacted, and the settlement is stable in the construction process.

Detailed Description

The technical solution of the present invention will be further described with reference to the following examples:

coral sand formations are distributed around the world in a large number of areas around the equator, including the east and west coast of africa, the markov ring reef, the large triangle of coral reefs in the north and east australia, the caribbean reef, etc. With the development of the world economy, a great deal of engineering construction is carried out in the region. Taking a Markov airport reconstruction and extension project as an example, the maximum depth of seawater in the construction area is 8 meters, and the method comprises the following steps:

step one, adopting a hydraulic filling construction method to fill coral sand to a depth above sea level and more than 1.7 m;

step two, completing coral sand blow filling in 2017 in 2 months, standing the blow filled coral sand pile for 2 months, and starting rolling treatment in 2017 in 4 months;

step three, spraying seawater on the upper surface of the coral sand pile, spraying water in an amount which can cause local water accumulation, and rolling after spraying water for 20 minutes;

step four, vibrating and rolling the upper part of the coral sand pile subjected to blow filling by adopting a large-tonnage rolling machine, wherein the tonnage of the large-tonnage rolling machine is 36 tons, the vibration frequency is 28 Hz-31 Hz, the advancing speed is 5KM/h, and the rolling is carried out for 4 times;

step five, repeating the operation of the step three and the operation of the step four for 8 times to compact the coral sand in the depth influence range;

continuously spraying seawater on the surface of the upper part of the coral sand pile, wherein the spraying amount reaches the local accumulated water, and rolling after spraying for 20 minutes;

seventhly, performing vibration rolling on the upper part of the coral sand pile by adopting a 26-ton vibration rolling machine, wherein the vibration frequency is 27 Hz-31 Hz, the line passing speed is not more than 5KM/h, and rolling for 4 times;

step eight, repeating the step six and the step seven until the sedimentation is stable; carrying out settlement observation in the rolling process, determining the stable condition of settlement, and rolling by a small-tonnage rolling machine to form a hard shell layer with a certain thickness on the surface layer;

and step nine, foundation detection, namely improving the dynamic penetration number in a depth range of 6m through dynamic penetration detection, detecting the dynamic penetration number in the depth range to be not less than 5 hits and dry density, detecting the dry density of a surface layer to be not less than 1.6g/cm3, detecting a static load test to be not less than 200kPa, detecting the soil-based reaction modulus to be not less than 55MPa, detecting the California bearing ratio to be 12%, subsequently carrying out settlement observation, and ensuring that the settlement is not more than 20mm by 12 months in 2017 to meet the design requirement.

And finally, controlling the settlement by certain rolling times (4 times).

Claims (1)

1. A method for processing coral sand stratum foundation by adopting large-tonnage vibration rolling is suitable for sea areas with seawater depth not greater than 8 meters, and is characterized in that: the method comprises the following steps:

step one, adopting a hydraulic fill construction method to hydraulic fill coral sand to a depth above sea level and more than 1.5 m;

step two, standing the coral sand pile subjected to blow filling for not less than 1 month;

step three, spraying seawater on the upper surface of the coral sand pile, spraying water in an amount which can cause local water accumulation, and rolling after spraying water for 20 minutes;

step four, performing vibration rolling on the upper part of the coral sand pile subjected to blow filling by adopting a large-tonnage rolling machine, wherein the tonnage of the large-tonnage rolling machine is not less than 36 tons, the vibration frequency is 28 Hz-31 Hz, the line passing speed is not more than 5KM/h, and the rolling is performed for 4 times;

step five, repeating the step three and the step four for 8 times;

step six, spraying seawater on the upper surface of the coral sand pile, spraying water in an amount which can cause local water accumulation, and rolling after spraying water for 20 minutes;

seventhly, performing vibration rolling on the upper part of the coral sand pile by adopting a 26-ton vibration rolling machine, wherein the vibration frequency is 27 Hz-31 Hz, the line passing speed is not more than 5KM/h, and rolling for 4 times;

step eight, repeating the step six and the step seven until the sedimentation is stable;

and step nine, foundation detection, including dynamic sounding detection, dry density detection, static load test detection, soil foundation reaction modulus detection and California bearing ratio detection.