216 results about "Subgrade soils" patented technology

The invention relates to a novel highway embankment widened structure. The original roadbed slope of the structure is trimmed into a step shape, a high pressure jet grouting pile is disposed below an original roadbed slope cushion layer, pressurized continuous grouting is employed at an original roadbed cushion layer to form a slurry solid bearing plate, parts of pore cavities of the original roadbed are recharged with fine aggregate concrete or mortar; foundation treatment piles are employed to reinforce the foundation of a widened area, a drainage cushion layer is laid throughout the top of the foundation treatment piles; an earthwork cloth is laid on the drainage cushion layer, a cement soil plate is disposed on the earthwork cloth, high strength reinforcing mesh sheets are disposed in the cement soil plate; and the widened area embankment is formed by layered filling of excavation soil and light filler in a construction process. The structure provided by the invention can reinforce the bearing capacity of roadbed soil on both sides of the widened area and the original roadbed slope strength, and enhance the integrality of the embankment structure, reduce longitudinal cracks induced by differential settlement and the like at the juncture of new and old roadbeds, thus having good technical and economic benefits. The invention also discloses a construction method of the novel highway embankment widened structure.

The invention relates to a method for designing a jointless track of a long and large bridge girder longitudinal butt plate type ballastless track for a high-speed railway. According to the method provided by the invention, ANSYS software is utilized to establish a latitude vertical space coupling statics model of the jointless track of the long and large bridge girder longitudinal butt plate type ballastless track for the high-speed railway, and ABAQUS software is utilized to establish a space coupling kinetic model. According to the method, the compositions of systems such as a steel rail, a fastener, track plates, a slurry placement layer, bed plates, a sliding layer, a consolidation mechanism, high-strength extruded sheets and L-shaped side check blocks, and structures such as supporting layers on a subgrade soil body and a road foundation and the action of high-speed vehicles are taken into full consideration, and friction factors of sliding layers on different bridge or friction plates, the longitudinal resistance of the fastener, the temperature difference of the bridge girder, the temperature difference of a ballastless track structure, the elastic modulus of the slurry placement layer and the like are calculated, so that the stress and deformation of the track and the bridge girder are obtained. The method provided by the invention is suitable for the design and computational check of the jointless track of the long and large bridge girder longitudinal butt plate type ballastless track for the high-speed railway, and providing service for the design calculation as well as conservation and maintenance of the high-speed railway.

The invention provides a settlement control method in a process of enabling a subway tunnel to penetrate through the existing railway. The settlement control method comprises the steps: establishing a line structure-subgrade-soil layer three-dimensional calculation model by utilizing a dynamic finite element theory to simulate and analyze deformation relations of a tunnel structure, a soil layer and a track foundation caused by subway tunnel construction at different tunnel burial depths in different excavation manners; by combining the existing subway tunnel under-through construction documents, summarizing and concluding deformation influence factors and a deformation influence rule to the existing line foundation, and an influence rule to track irregularity caused by tunnel excavation during subway tunnel under-through construction; based on correlation requirements on track static geometric dimensions and dynamic quality allowable deviation management in the existing railway deformation control index system, proposing a settlement control index in the process of enabling the subway tunnel to penetrate through the existing railway; if during construction, the real-time monitored subgrade settlement amount is over the settlement control index, giving out an alarm. The invention can relieve, eliminate and avoid adverse effects to the ground surface settlement of the crossed existing railway caused by subway construction, and provides a means to scientifically and reasonably developing safety evaluation of the subway tunnel construction.

A testing machine for testing the mechanical parameters of subgrade materials under the freezing and thawing cycle comprises a temperature controlled system, a dynamic load system, a mechanical parameter testing system, a data acquisition system and an electronic control system; the temperature controlled system is used for simulating the freezing and thawing cycle of subgrade soil in the real environment; the electronic control system is used for controlling the dynamic load system during the freezing or thawing process, thereby enabling the dynamic load system to output various frequencies to simulate the traffic load; the mechanical parameter testing system is used for measuring the total settlement and strain; the deflection and strain value is collected by the data acquisition system in a real-time manner; and after processing, the numerical values, the time-displacement curve and the strain-time curve are displayed. The invention tests the mechanical characteristic parameters of the subgrade materials and monitors the frost-heave capacity, the pavement deflection value and the deformation of the materials during the process of the dynamic load freezing or thawing, quickly and stably simulates the environment necessary for testing, and measures the mechanical performance index of the materials, thereby providing design parameters for road engineering in a seasonal frost region, ensuring that a road in the seasonal frost region fulfills the service life as designed, and improving the measuring accuracy with accurate calculation result.

The invention discloses a large-sized box jacking control construction method capable of enhancing accuracy. The construction method comprises the following steps of: arranging a plurality of cement stirring piles into a foundation pit on one side of a railway on which a frame bridge is required to be paved; reinforcing a subgrade soil body below the railway with cement water glass slurry to enhance the bearing force of a foundation; jacking a large-sized box towards the lower side of the railway by using jacking equipment; and preventing the large-sized box from being subjected to phenomena such as deviation, head tying or head raising and the like by different measures. By adopting the method, the positioning accuracy of the large-sized box can be ensured, good engineering quality and high safety are achieved, and normal operation of the existing railway is not obstructed.

The invention relates to the field of road engineering, in particular to a measurement system for an unsaturated infiltration coefficient of subgrade soil and a related measurement method of the system. The measurement system for the unsaturated infiltration coefficient of the subgrade soil comprises a test sample containing device and a water supply device, the test sample containing device comprises a test sample containing part, a temperature measurement device and a medium suction measurement device are further arranged in a test sample containing cavity, the system further comprises a topcover which covers an opening in the test sample containing part, and the top cover is detachably connected with the test sample containing part; the test sample containing part further comprises anair guide channel, a water inlet channel and a drainage channel. The measurement system for the unsaturated infiltration coefficient of the subgrade soil and the related measurement method of the system have the advantages of integrated functions, convenient operation, precise control and the like, dynamic data can be collected in real time in the whole testing process, the measurement precision is greatly improved through internal checking, and the unsaturated infiltration coefficient under change of the moisture content of a soil sample is automatically measured.

The invention belongs to the technical field of high-speed railway subgrade engineering, and particularly relates to a high-speed railway subgrade structure for saline soil areas. The high-speed railway subgrade structure comprises a road cutting structure, wherein the road cutting structure comprises a subgrade bed surface layer and a subgrade bed bottom layer; a partition layer is arranged at the bottom of the subgrade bed bottom layer; a surface drain system is arranged at each of two sides of the road cutting structure, an underground drain system is arranged at the bottom of the surface drain system; the partition layer extends outwards along two sides of the longitudinal direction to intersect the surface drain system or underground drain system. Based on the compact connection of the surface drain system, the underground drain system, the partition layer and the like with the components thereof to achieve special purposes, the high-speed railway subgrade structure is simple, and can effectively cut off capillary water migration pathways between subgrade soil and the road cutting subgrade bed structure, thereby avoiding the problems of salt expansion, break-up expansion, melt sinking and the like and guaranteeing the long-term normal use of high-speed railway subgrade engineering.

A reinforcing geotextile mat and an embankment method using the same. The mat comprises support means for supporting backfilled soil at one end or both ends of the mat. The support means comprises a horizontal support section for supporting the backfilled soil in a vertical direction; a vertical support section for supporting the backfilled soil in a horizontal direction; and an inclined support section defined with openings through which the backfilling soil passes and inclinedly embedded in the backfilled soil. The method comprises the steps of positioning a reinforcing geotextile mat on the ground or hardened embankment soil; inserting external support members in horizontal, vertical and inclined receiving portions of the mat; and backfilling horizontal, vertical and inclined support sections of the mat with soil, and then placing and hardening embankment soil on the mat. These steps are implemented one or more times.

The invention provides an indoor testing method for a roadbed soil deformation modulus, aiming to solve the problems of the prior art that a testing method for a roadbed soil deformation modulus E has the defects of time and labor consumption, harsh testing conditions, higher cost and the like. The indoor testing method for the roadbed soil deformation modulus is characterized in that a compaction soil sample and a compaction cylinder are integrally used as a test piece of the indoor testing method of the roadbed soil deformation modulus; load values and corresponding deformations of each loading or unloading detected by first loading and unloading as well as second loading and unloading are adopted, and a load-settling volume curve is drawn according to the load values and the corresponding deformations of each loading and unloading; and then the roadbed soil deformation modulus is solved through calculating. The indoor testing method for the roadbed soil deformation modulus has the advantages that the defect that the roadbed soil deformation modulus E can be tested only on the spot of the prior art is overcome, and the testing of the roadbed soil deformation modulus E is more accurate, convenient and quick.

The invention provides a method for improving a heavy haul railway subgrade by the use of fiber-reinforced stabilized soil. According to the method, monofilament bunched fiber and a soil stabilizer are doped in heavy haul railway subgrade soil, wherein dosage of the monofilament bunched fiber is 0.05-0.5% of the weight of dry soil, length of the fiber is 3-54 mm, dosage of the soil stabilizer is 3-7% of the weight of dry soil, and a formula of the soil stabilizer contains, by weight, 30-42% of aluminosilicate, 18-24% of ferrous aluminate, 10-16% of sulfate, 10-16% of sulfite, 16-20% of sulfoaluminate, 4-8% of chloride and 3-6% of oxide; and jet machining molding, spraying, piling and filling, rolling forming and maintenance are carried out successively. The fiber-reinforced stabilized soil has good three-dimensional engineering characteristic, water stability, resistance to deformation, shearing resistance, tensile strength, crack resistance, local deformation improvement and other engineering characteristics, and can be used in subgrade constructions for railway, road and the like.

The invention provides a subgrade settlement prediction method and a subgrade settlement prediction system, and relates to the field of traffic building engineering. The method comprises the steps that a first analysis module analyzes and predicts a subgrade soil body under the action of traffic load to obtain an accumulated deformation value; a second analysis module analyzes and predicts subgrade soil body solidification settlement generated by excess pore water pressure dissipation to obtain a solidification settlement value; then a long-term settlement value calculation formula is utilized to calculate the accumulated deformation value and the solidification settlement value to obtain a long-term settlement value. Compared with a prediction method in the prior art, the subgrade settlement prediction method takes into account of the subgrade soil body solidification settlement generated by the excess pore water pressure dissipation, in combination with a finite element method and a test result, the problem is solved that the traffic load high vibration frequency is high and the calculation amount is big at the same time, moreover, the method is reasonable and feasible, the long-term settlement value of the subgrade soil body under the traffic load can be more accurately predicted, and a reference basis is provided for the aspects of design, construction, operation, maintenance and the like of traffic engineering.

The invention discloses an ultrasonic technology-based method for detecting and evaluating damage of subgrade soil materials in seasonal frozen regions. The method comprises the following steps: an initial state sample and a test sample are prepared according to an evaluation scheme on the basis of a formed sample meeting requirements of subgrade soil; the initial state sample is not subjected tofreeze-thaw cycles and has humidity being the evaluation standard moisture content; the test sample is a soil sample which is subjected to freezing and thawing cycling and has humidity at the requiredmoisture content for testing; the initial state sample and the test sample are both subjected to geometric parameter measurement and ultrasonic wave velocity test, the volume deformation rate of thetest sample and the longitudinal wave velocity of the test sample and the initial state sample are obtained, the longitudinal wave velocity, the moisture content and the volume deformation rate of thetest sample are measured according to the longitudinal wave velocity and moisture content of the initial state sample, and the damage variable of the test sample is calculated. Therefore, with the method, the damage degree of soil can be evaluated accurately, comprehensively and non-destructively and the damage mechanism can be reflected without destructive tests.

A bio-enzyme curing material integrated road paving construction method comprises the following steps: (1) designing mixing ratio of bio-enzyme curing materials, namely, 1.1) selecting raw materials,and 1.2) designing the mixing ratio, and recommending mixing ratio to the following bio-enzyme curing material for a road; and (2) performing bio-enzyme curing material integrated road paving construction, namely, 2.1) designing the mixing ratio of the bio-enzyme curing material, 2.2) stirring the bio-enzyme clinker at field (a method for stirring on the road), and 2.3) conveying the bio-enzyme clinker meeting the construction mixing ratio and technical requirement to a working surface; modifying the soil quality of a roadbed; integrally paving a bottom base layer, a base layer or a surface layer; shaping; and rolling. According to the method, the suitable mixing ratio is designed and the bio-enzyme curing material is designed based on different structure layers of the roadbed and a pavement; and meanwhile, related construction process links are improved; and the current demand on constructing an environmentally-friendly and resource-saving highway in current novel urbanization processcan be met.

The invention relates to a construction method of a subgrade foam concrete filling technology adjacent to an existing metro facility. The construction method comprises the following steps of measurement and setting-out, foundation pit excavation, template mounting, foam concrete mixing and pouring, steel wire mesh laying and concrete maintenance. Foam concrete is poured in a blocking and layeringmanner and is divided into four sections longitudinally, into a left side and a right side transversely and into two layers vertically. The construction method has the beneficial effects that comparedwith ordinary concrete, the foam concrete has the characteristics of light weight, high strength, energy conservation and waste utilization; the advantages of the foam concrete is effectively exertedwhile the strength is improved; and in addition, by utilizing the foam concrete with different strengths for blocking and layering filling, the cost can be effectively saved, and the purposes of economy and effectiveness are achieved. By adopting the construction method provided by the invention, the additional load after subgrade soil replacement can be effectively reduced, the strength is ensured, the stability and safety coefficients of road engineering are increased, the engineering cost can also be lowered at the same time, the maintenance cost is reduced, and the social benefit is increased.

The invention relates to a soft soil roadbed drainage prepressing rear blocking structure. The structure is characterized in that discrete material short piles, plastic drainage plates, a horizontal drainage pad layer, vertical grouting pipes and a horizontal grouting pipe are structurally included, the discrete material short piles are arranged below the horizontal drainage pad layer, the vertical grouting pipes and the plastic drainage plates are arranged in the discrete material short piles, the horizontal drainage pad layer is laid below roadbed filler, the horizontal grouting pipe is laid in the horizontal drainage pad layer, the horizontal grouting pipe and the vertical grouting pipes are communicated through tee joints, after roadbed drainage prepressing is finished, grout is injected into the discrete material short piles and the horizontal drainage pad layer through the vertical grouting pipes and the horizontal grouting pipe to form vertical grouting sealed short piles and a grouting solidified pad layer bearing plate. According to the structure, performance of readbed soil is improved through drainage consolidation of the roadbed soil, the problem that pre-construction settlement of a road segment processed in a drainage consolidation method is exceedingly large can be solved, and meanwhile, bearing capacity and integrity of the roadbed can be improved through grout injection. The invention further discloses a construction method of the preceding structure.

The invention discloses a permeability evaluation method of a permeable asphalt pavement based on fluid-solid coupling analysis. The method comprises the steps of determining material parameters and hydrologic parameters of structural layers of the pavement through a laboratory test, establishing unsaturated seepage models of the structural layers, establishing a numerical model of a permeable asphalt pavement system, simulating an initial moisture field in the pavement system, analyzing a rainfall infiltration process based on a saturated-unsaturated fluid-solid coupling theory, simulating adynamic variation of the moisture field under a rainfall condition, and evaluating permeability of the permeable asphalt pavement. The method comprehensively considers the influence of the initial moisture field caused by underground water and subgrade soil types in a pavement scope on the internal permeability of the pavement, and relatively accurately simulates mutual coupling and influence of the rainfall infiltration process and an underground water level fluctuation; the laboratory test and numerical simulation are combined to achieve transient analysis of the internal rainfall infiltration process of the permeable asphalt pavement system; and the method can more visually evaluate the permeability of a road structure and is practical, feasible and efficient.

The invention discloses a jujube and cotton intercrop moisture adjusting device and moisture adjusting method. The jujube and cotton intercrop moisture adjusting device comprises an irrigation system,a moisture maintaining system and a drainage system. The moisture adjusting device is provided with a first pipeline and a second pipeline, and can conditionally irrigate jujube trees and cotton according to different requirements for moisture at different growth stages of the jujube trees and the cotton; the moisture maintaining system is used for maintaining intercrop field moisture and reducemoisture dissipation; the drainage system is used for timely draining excessive moisture of fields; the soil structure in the intercrop fields is changed, bottom-layer soil, a clay layer, a mixed soillayer, a surface layer, subgrade soil and upper-layer soil are set, so that the water holding capacity of the soil in the intercrop fields is improved; and besides, according to the characteristic ofbeing high in amount of water required for later stage of the cotton, improved clay is paved in a cotton planting ridge, the water holding capacity of the cotton planting ridge is further improved, and the necessary irrigation frequency is reduced.

The invention belongs to the field of computer tests and particularly relates to a CBR numerical test method for soil-stone filled subgrade soil. Simulation is performed through discrete element software PFC2D. The method comprises the steps that first, particles are grouped, the grouping range of each group of particles is determined, and an initial void ratio is preset; second, a domain and a boundary wall are defined, and traversing conditions are set; third, a soil-stone filled particle two-dimensional discrete element constitutive model and relevant parameters are selected; fourth, particle balls are generated, external conditions are applied, and a two-dimensional discrete element test piece of a soil-stone filled body is obtained through calculation and analysis; and last, loading conditions are applied, a California bearing ratio (CBR) test is simulated in PFC2D, test data is recorded, and a CBR value is calculated. The method is an efficient and accurate computer numerical simulation method, and the process of loading the CBR test value to the soil-stone mixture molding test piece is simulated to deeply study mechanical properties of the soil-stone filled subgrade soil.

The invention discloses an unsaturated roadbed soil freeze-thaw cycle model test system, relates to a freeze-thaw cycle test device, and aims to solve the problem that an existing freeze-thaw cycle test device cannot truly and accurately reflect the comprehensive influence of temperature, moisture and load in the actual freeze-thaw cycle process, wherein the device comprises a test bin, a controlsystem and a data acquisition system, and the test bin comprises a sleeve, a heat preservation body and a water permeable part; a test piece is loaded in the sleeve, the side wall is hermetically wrapped with a thermal insulator, and the water permeable part is arranged at the bottom; the control system comprises a temperature control system, a moisture control system and a load control system; the temperature control system comprises a temperature control chamber, an upper temperature control disc and a lower temperature control disc; the temperature control chamber covers the test bin; the upper temperature control disc and the lower temperature control disc are respectively arranged at the top and the bottom of the sleeve; the moisture control system is communicated with the bottom of the test piece through a water supplementing pipe; the load control system is arranged at the top of the sleeve; the data acquisition system comprises a temperature acquisition system, a moisture acquisition system and a displacement acquisition system.

The invention relates to a construction method of pouring a retailing backwall using foam light soil in a highway reconstruction and extension project. Firstly a base is cleaned and compacted, a layerof broken stones with the thickness of 30 cm is laid, steps are arranged along the route driving direction and along one side, close to a road center line, of the cross section direction, a convex step is poured by using a form hanger on the side close to a side slope, and the steps are arranged for better lapping of the foam light soil and subgrade soil. Waterproof geomembranes are laid on the lowest layer and the topmost layer of a foam light soil structure, and earthwork standard rooms are laid on the positions which are respectively 50 cm from the bottom layer and 50 cm from the top layerto enhance the overall strength. By adopting the construction method, under the condition that the area at the retailing backwall is small and is not favorable for construction of a large-scale instrument, the construction can be simplified, the operation is convenient, by utilizing the features of quick early strength formation and good integrality of the foam light soil, the dependency on lateral wrapping soil is reduced, and template supports are used instead for pouring. The construction method has a relatively good effect on reducing bump at bridge-head.

The invention discloses a method of estimating dynamic elastic modulus of subgrade soil based on state variable and stress variable. The method includes: using a pressure plate instrument to measure matrix suction of the subgrade soil, and establishing a soil-water characteristic curve to obtain model parameters under different compactness degrees; using a dynamic triaxial instrument to perform dynamic elastic modulus test of subgrade soil to obtain dynamic elastic modulus value of the subgrade soil; establishing a subgrade soil dynamic elastic modulus estimation model based on a state variable and a strain variable; establishing a relational equation between estimation model parameters and subgrade soil physical property indexes. The problem is solved that existing methods of estimating elastic modulus give no consideration to subgrade soil state variable, strain variable, and subgrade soil physical properties.

The invention discloses a method for improving the frozen stability of a highway subgrade in a seasonal frozen region. According to the method, double subgrade isolating layers (namely an upper isolating layer and a lower isolating layer) of the subgrade is adopted, wherein the lower isolating layer is used for isolating capillary water under the maximal highway frozen depth for many years and reducing ice gathering amount of a subgrade soil body to the utmost extent; meanwhile, the upper isolating layer is used for isolating pavement water seepage at the top of the subgrade and draining water horizontally; the upper isolating layer and the lower isolating layer act together to realize a long-term stability purpose of the subgrade. By the adoption of the double-isolating-layer technology, water stability and the frozen stability of the subgrade can be well effectively ensured, so that deficiencies in the design of highways in cold areas in China can be made up.

The invention discloses a method for rapidly determining soil-water characteristic curves and dynamic rebound modulus model parameters. The method is characterized in that firstly, a basic physical performance index test of subgrade soil is carried out; secondly, a pressure plate instrument is used for measuring matrix suction, a soil-water characteristic curve is established, and then a roadbed soil rebound modulus test is conducted through three movable axes, the rebound modulus values are obtained, the roadbed soil rebound modulus estimation model parameters are obtained through fitting andsolving, and finally a relation equation between the model parameters and roadbed soil physical property indexes is established. According to the method, the test quantity is greatly reduced, the test cost is reduced, and the problems of long model parameter determination time, high cost consumption and the like of an existing rebound modulus and soil-water characteristic curve pre-estimation model are solved.

The invention discloses a dynamic subgrade soil resilience modulus prediction method based on matric suction and minimum body stress. The dynamic subgrade soil resilience modulus prediction method comprises: determining the matric suction of subgrade soil by using a pressure plate meter, and establishing a soil water characteristic curve to obtain model parameters under different compactness degrees; carrying out resilience modulus test by using a dynamic triaxial tester to obtain a subgrade soil resilience modulus value; establishing the logarithmic function relationshio equation between thesubgrade soil matric suction and the resilience modulus; and finally providing the dynamic subgrade soil resilience modulus prediction method based on the matric suction, the minimum body stress and the octahedron shear stress. With the method of the present invention, the humidity state and the stress state of the subgrade soil can be simultaneously considered, the established prediction model has clear physical meaning and simple structure, the parameters of the model can be determined by using the conventional dynamic triaxial tester, and the method is suitable for promotion application.

The invention discloses a subgrade settlement monitoring system based on a MEMS sensor, which comprises a plurality of rigid pipes connected head-to-tail in sequence and MEMS inclination sensors fixed in each rigid pipe, adjacent rigid pipes are flexibly connected by flexible pipes At the same time, a cable splitter is provided in each flexible tube, and each MEMS inclination sensor is connected to each cable splitter through a cable branch line, and each cable splitter is connected through a cable bus. Connection, each section of rigid pipe can only rotate relative to each other without relative displacement, and each section of rigid pipe will tilt and rotate with the subgrade soil settlement, and the MEMS inclination sensor fixed in each section of rigid pipe measures the inclination angle of each section of rigid pipe The change of the measurement data is transmitted through the cable branch, the cable branch and the cable bus, so as to obtain the subgrade settlement information in the monitoring area and realize the automatic monitoring of subgrade settlement.