粉细砂层声频振动注浆模拟试验研究
发布时间：2018-12-27 17:30
【摘要】：作为地下综合管廊、地铁、隧道等建设工程中常见的软弱不良地层——粉细砂土层,因粒径小、结构松散、稳定性差,故其注浆加固防渗处理工作,一直是地质工程界研究的热点。声频振动钻进注浆法利用粉细砂层易液化特性,采用高频振动和高压力提高浆液的扩散性,是一种新型的、有前景的注浆工艺方法。本文对该新型注浆方法进行了探索研究。首先,调研浆液的流变性,通过对注浆浆液在地层中的扩散模型研究,基于声频振动钻进注浆机理,建立声频振动注浆模型。其次,针对目前振动注浆室内试验的不足,研制了声频振动钻进注浆试验平台,包括振动发生装置、传动杆体、约束支撑装置、砂土箱、浆液输送管路等。试验平台可实现振源特性相关的振动频率、激振力、振动时间的调控,并可调节浆液的压力和流量。再次,根据粉细砂地层的主要工程性质,配制实验用注浆浆液,并对浆液的理化性质进行测试研究。随后,进行静压注浆试验,确定试验砂土的适宜注浆压力并作为后续试验的对照实验。最后,开展声频振动注浆模拟试验研究,并得到以下结论:(1)振源振频越接近砂土体的固有频率,浆液的注入量及扩散半径越大,注浆加固效果越好。当振频与粉细砂土固有频率偏差较大时,振动冲击作用改善注浆环境的效果不够明显,反而会因为振冲作用使孔壁间隙扩大,尤其在钻杆埋深较浅、上覆土压力较小时,更容易产生冒浆,不利于注浆效果。所以根据实际工况选择适宜振频,才能实现工程施工的优质高效。(2)激振力的大小对声频振动注浆效果的影响并不明显,在适宜频率的振动作用下,注浆效果不会随激振力的改变而发生实质性变化。(3)振动作用起始阶段,浆液扩散速率增长较快,浆液固结体迅速变大。随着振动作用时间的延长,浆液扩散半径也会逐渐增大,只是增速放缓,最后速率趋近于零。综上所述,振动频率是决定注浆效果的关键性因素。针对不同粉细砂地层,调节振动频率,配合高压进行注浆作业,可有效改善地层可注性,提升浆液的注入量,扩大浆液的扩散半径,增大浆液固结体体积,取得良好的注浆效果。
[Abstract]:As a common weak and bad stratum in underground comprehensive pipe gallery, subway, tunnel and other construction projects, the silty sand soil layer, because of its small particle size, loose structure and poor stability, is used to reinforce and prevent seepage treatment by grouting. It has always been a hot spot in the field of geological engineering. Sound frequency vibration drilling grouting method is a new and promising grouting method, which utilizes the liquefaction characteristics of fine silty sand layer and uses high frequency vibration and high pressure to improve the diffusivity of the slurry. In this paper, the new grouting method is studied. Firstly, the rheological behavior of grouting fluid is investigated, and the acoustic vibration grouting model is established by studying the diffusion model of grouting fluid in stratum and based on the mechanism of acoustic vibration drilling grouting. Secondly, aiming at the deficiency of vibration grouting laboratory test at present, an audio frequency vibration drilling grouting test platform is developed, including vibration generator, transmission rod body, restraint support device, sand box, slurry conveying pipeline and so on. The test platform can adjust the vibration frequency, exciting force and vibration time, and adjust the pressure and flow rate of the slurry. Thirdly, according to the main engineering properties of silty sand formation, the grouting fluid for experiment is prepared, and the physical and chemical properties of the slurry are tested and studied. Then, a static pressure grouting test was carried out to determine the appropriate grouting pressure of the test sand and to be used as a control experiment in the follow-up test. Finally, the simulation experiment of acoustic vibration grouting is carried out, and the following conclusions are obtained: (1) the vibration frequency of vibration source is close to the natural frequency of sand body, the larger the injection amount and diffusion radius of slurry, the better the grouting reinforcement effect. When the vibration frequency and the natural frequency of silty sand soil deviate greatly, the effect of vibration shock on improving grouting environment is not obvious, but the hole wall gap will be enlarged because of vibration and impact, especially when the drill pipe is buried in shallow depth and the overlying earth pressure is small. It is easier to produce grouting, which is not conducive to grouting effect. Therefore, according to the actual conditions, select the appropriate vibration frequency, in order to achieve the high quality and efficiency of engineering construction. (2) the magnitude of the exciting force on the sound vibration grouting effect is not obvious, under the appropriate frequency of vibration, The grouting effect will not change materially with the change of the exciting force. (3) in the initial stage of vibration the slurry diffusion rate increases rapidly and the slurry consolidation body increases rapidly. With the extension of vibration time, the slurry diffusion radius will gradually increase, but the growth rate will slow down, and the final rate will reach zero. In conclusion, the vibration frequency is the key factor to determine the grouting effect. According to different silty sand strata, regulating vibration frequency and grouting with high pressure can effectively improve the injectability of stratum, increase the injection quantity of slurry, enlarge the diffusion radius of slurry, and increase the volume of slurry consolidation body. Good grouting effect has been achieved.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU753.8
，
本文编号：2393380
[Abstract]:As a common weak and bad stratum in underground comprehensive pipe gallery, subway, tunnel and other construction projects, the silty sand soil layer, because of its small particle size, loose structure and poor stability, is used to reinforce and prevent seepage treatment by grouting. It has always been a hot spot in the field of geological engineering. Sound frequency vibration drilling grouting method is a new and promising grouting method, which utilizes the liquefaction characteristics of fine silty sand layer and uses high frequency vibration and high pressure to improve the diffusivity of the slurry. In this paper, the new grouting method is studied. Firstly, the rheological behavior of grouting fluid is investigated, and the acoustic vibration grouting model is established by studying the diffusion model of grouting fluid in stratum and based on the mechanism of acoustic vibration drilling grouting. Secondly, aiming at the deficiency of vibration grouting laboratory test at present, an audio frequency vibration drilling grouting test platform is developed, including vibration generator, transmission rod body, restraint support device, sand box, slurry conveying pipeline and so on. The test platform can adjust the vibration frequency, exciting force and vibration time, and adjust the pressure and flow rate of the slurry. Thirdly, according to the main engineering properties of silty sand formation, the grouting fluid for experiment is prepared, and the physical and chemical properties of the slurry are tested and studied. Then, a static pressure grouting test was carried out to determine the appropriate grouting pressure of the test sand and to be used as a control experiment in the follow-up test. Finally, the simulation experiment of acoustic vibration grouting is carried out, and the following conclusions are obtained: (1) the vibration frequency of vibration source is close to the natural frequency of sand body, the larger the injection amount and diffusion radius of slurry, the better the grouting reinforcement effect. When the vibration frequency and the natural frequency of silty sand soil deviate greatly, the effect of vibration shock on improving grouting environment is not obvious, but the hole wall gap will be enlarged because of vibration and impact, especially when the drill pipe is buried in shallow depth and the overlying earth pressure is small. It is easier to produce grouting, which is not conducive to grouting effect. Therefore, according to the actual conditions, select the appropriate vibration frequency, in order to achieve the high quality and efficiency of engineering construction. (2) the magnitude of the exciting force on the sound vibration grouting effect is not obvious, under the appropriate frequency of vibration, The grouting effect will not change materially with the change of the exciting force. (3) in the initial stage of vibration the slurry diffusion rate increases rapidly and the slurry consolidation body increases rapidly. With the extension of vibration time, the slurry diffusion radius will gradually increase, but the growth rate will slow down, and the final rate will reach zero. In conclusion, the vibration frequency is the key factor to determine the grouting effect. According to different silty sand strata, regulating vibration frequency and grouting with high pressure can effectively improve the injectability of stratum, increase the injection quantity of slurry, enlarge the diffusion radius of slurry, and increase the volume of slurry consolidation body. Good grouting effect has been achieved.
【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU753.8
，
本文编号：2393380
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