Study On Reinforcement Effect Of Dredging Foundation Reinforced By Rice Straw Rope

In order to ensure the smooth passage of the channel,China will carry out river dredging projects every year.The resulting sludge can be used in a dredging process,but the silt foundation formed by the dredging has a very high moisture content.Vacuum preloading technology is often used in engineering to reduce the water content.China is also a large agricultural country with abundant crop straw resources,but nearly 160 million tons of straw are burned in the open air every year.The resulting atmospheric pollutants cause a serious drop in air quality.To this end,China's Ministry of Agriculture and Rural Affairs issued a notice to promote the comprehensive utilization of straw.Fiinding more ways to use straw resources is a top priority.Some scholars have proposed using straw drainage as a vertical drainage body when using vacuum preloading technology to reduce the moisture content of the foundation.On the one hand,the straw drainage body can provide a seepage path for the sewage under the membrane to achieve the purpose of drainage;on the other hand,the straw drainage body can improve the bearing capacity of the dredged foundation.In addition,this measure can also improve the recycling rate of straw resources and solve the pollution problem of plastic drainage boards.At present,some scholars have verified the drainage performance of the straw drainage body,but there are few studies on the reinforcement effect of the straw drainage body on the dredged foundation.In order to study the reinforcement effect of rice straw rope on the dredged silt,the tensile test and the pull test were carried out in this paper.The tensile properties of the straw straw and plastic drainage board and the drawing between the straw and the plastic silt were compared.Based on the foundation bearing capacity calculation formula,the influences of the five factors of the spacing,the depth of the installation,the interface friction strength,the foundation width and the tensile strength of the straw stalk rope on the bearing capacity of the foundation are analyzed.It provides a theoretical basis for the straw straw rope to reinforce the foundation.The innovative results obtained are as follows:1.The degradation of rice straw rope in water is divided into three stages,namely rapid degradation stage,idling degradation stage and secondary degradation stage.After soaking for 60 days,it was found that the degradation of the sample mainly occurred in the rapid degradation stage,and the average mass loss rate was 44.3%,accounting for 80.9%of the total.2.The straw straw rope is the main force of the straw fiber,and the damage is gradually transferred from the relatively weak secondary straw fiber to the main straw fiber;The plastic drainage board is the same as the core board and the filter membrane,and the filter membrane is destroyed before the core board.3.The interfacial frictional strength of rice straw rope and dredged silt decreased with the increase of soaking time;it increased greatly with the increase of normal stress.Under the action of high normal stress,the interface shear strength between the sample and the silt consists of two parts,namely the interfacial shear strength between the sample and the "mud" and the interfacial shear strength between the "mud" and the silt.4.Reducing the spacing of the installation and increasing the foundation width,increasing the depth of the installation,the interface friction strength and the tensile strength of the straw straw rope can improve the bearing capacity of the foundation.Figure 42 table 10 reference 55.