Hard rock tunneling muck recycling improvement process construction method

Abstract

The invention discloses a hard rock tunneling muck resource improvement process method, which belongs to the technical field of muck resource utilization, and comprises the following steps: mixing hard rock tunneling muck with a dehydrating agent, uniformly stirring, covering and braising for 8-12 hours, crushing, stirring and mixing to obtain pretreated muck; and mixing the pretreated muck, a powder soil stabilizer and a reinforcing filler, stirring and mixing for 30-40 minutes at the speed of 500-600r / min, and crushing, stirring and mixing to obtain the resource improved muck. Modified cellulose nanowhiskers, modified graphene oxide, chlorogenic acid modified chitosan and hydroxyethyl cellulose in the reinforcing filler are mixed to form a three-dimensional network structure combined by hydrogen bonds, so that the effect of transferring stress is achieved, the mechanical property of the muck-based concrete is enhanced, and the durability of the muck-based concrete is improved. The chlorogenic acid modified chitosan and the hydroxyethyl cellulose serve as a framework structure of the muck and can be adsorbed to the surface of the muck, the compactness of the muck is further enhanced, and the mechanical performance is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of resource utilization of construction waste, and particularly to a resource improvement process method for hard rock tunneling construction waste. Background Art

[0002] Engineering construction waste mainly comes from projects such as tunnel traffic, road construction, and site leveling. It is characterized by huge stockpiles, wide sources, complex compositions, and large differences. The huge amount of engineering construction waste not only pollutes the environment, but also causes waste of land resources and has potential safety hazards. Therefore, improving the waste engineering construction waste for use as subgrade filler and realizing resource utilization is an important way to promote renewable development in the highway field. Currently, the common method for improving engineering construction waste is to directly transport it out for discharge and let it dry naturally, but the treatment efficiency is low and it is easy to cause secondary pollution, etc. The improvement methods of engineering construction waste mainly include physical improvement, chemical improvement, and biological improvement.

[0003] Treating engineering construction waste with dehydrating agents and construction waste solidifying agents can reduce the water content of the engineering construction waste, and has good fluidity and appropriate consistency, and is widely used in building materials, such as for brick making, road construction, etc. However, the mechanical properties of the building materials prepared from engineering construction waste are poor, which affects the application of the construction waste in building materials, and there are a large number of pores in the engineering construction waste, and the compactness is poor. Summary of the Invention

[0004] The purpose of the present invention is to provide a resource improvement process method for hard rock tunneling construction waste: calcium carbonate particles are formed on the surface of cellulose nanocrystals modified with polydopamine, and the formed nano-calcium carbonate particles can penetrate into the pores of the construction waste, improve the compactness of the construction waste, and enhance the mechanical properties of the construction waste; nano-aluminum oxide is formed on the surface of graphene oxide, providing a large number of rough surfaces, increasing the contact area with the construction waste, so that the graphene oxide loaded with nano-aluminum oxide is tightly combined with the construction waste, improving the mechanical properties of the construction waste; octamethylcyclotetrasiloxane is grafted on the surface of the graphene oxide loaded with nano-aluminum oxide, and octamethylcyclotetrasiloxane can react with the organosilicon in the construction waste, thereby enhancing the binding force between the modified graphene oxide and the construction waste, further enhancing the compactness of the construction waste, and improving the mechanical properties of the construction waste; the modified cellulose nanocrystals, modified graphene oxide, chlorogenic acid-modified chitosan, and hydroxyethyl cellulose are mixed to form a three-dimensional network structure bound by hydrogen bonds, which plays a role in transmitting stress and further enhances the mechanical properties of the construction waste-based concrete.

[0005] Technical problems to be solved by the present invention: Treating engineering muck with a dehydrating agent and a muck solidifying agent can reduce the water content of the engineering muck, and has good fluidity and appropriate consistency, and is widely used in building materials, such as for brick making, road construction, etc. However, the mechanical properties of the building materials prepared from engineering muck are relatively poor, which affects the application of muck in building materials, and there are a large number of pores in the engineering muck, and the compactness is poor.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A resource improvement process method for hard rock tunneling muck, comprising the following steps:

[0008] S1. Mix the hard rock tunneling muck with a dehydrating agent, stir evenly, cover and stuff for 8 - 12 h, and obtain pretreated muck through crushing and stirring and mixing.

[0009] S2. Mix the pretreated muck, a powder soil solidifying agent and a reinforcing filler, and stir and mix at a rate of 500 - 600 r / min for 30 - 40 min, and obtain resource-improved muck through crushing and stirring and mixing.

[0010] The reinforcing filler is obtained by mixing and reacting modified cellulose nanocrystals, modified graphene oxide, chlorogenic acid-modified chitosan and hydroxyethyl cellulose;

[0011] The modified cellulose nanocrystals are obtained by surface-modifying cellulose nanocrystals with polydopamine and then in-situ depositing calcium carbonate particles;

[0012] The modified graphene oxide is obtained by mixing graphene oxide, an aluminum nitrate solution and urea, carrying out a hydrothermal reaction, and then reacting with octamethylcyclotetrasiloxane.

[0013] Furthermore, the mass ratio of the hard rock tunneling muck to the dehydrating agent is (80 - 100):(5 - 7).

[0014] Furthermore, the dehydrating agent is quicklime.

[0015] Furthermore, the mass ratio of the pretreated muck, the powder soil solidifying agent and the reinforcing filler is (80 - 100):(4 - 6):(8 - 10).

[0016] Furthermore, the powder soil solidifying agent is composed of sodium methyl silicate, sodium alginate, sodium dodecylbenzenesulfonate, sodium chloride, lithium hydroxide and a polycarboxylate superplasticizer mixed in a mass ratio of (3 - 5):(0.6 - 1):(1 - 1.5):(0.8 - 1.2):(0.1 - 0.3):(0.2 - 0.4).

[0017] Furthermore, the reinforcing filler is specifically prepared by the following steps:

[0018] A1. Add cellulose nanowhiskers to Tris-HCl buffer, stir evenly, add dopamine, stir for 3 - 5 h, filter, wash, and dry to obtain polydopamine-modified cellulose nanowhiskers;

[0019] A2. Add calcium chloride to deionized water, stir until completely dissolved, add polydopamine-modified cellulose nanowhiskers, stir evenly, add ammonia water to adjust the pH to 7 - 9, place in a reaction kettle, introduce carbon dioxide and air, after stirring the reaction is completed, filter to collect the solid, and dry the solid to obtain modified cellulose nanowhiskers;

[0020] A3. Add graphene oxide to aluminum nitrate solution, stir evenly, add urea, place in a autoclave at 140 - 160 °C, carry out hydrothermal reaction for 5 - 8 h, cool to room temperature, filter to collect the gel, and calcine at 500 - 600 °C for 1 - 3 h to obtain graphene oxide loaded with nano-aluminum oxide;

[0021] A4. Add graphene oxide loaded with nano-aluminum oxide to deionized water, stir evenly, add sulfuric acid and octamethylcyclotetrasiloxane, heat up to 55 - 65 °C, stir and react for 2 - 4 h, cool to room temperature, filter, wash, and dry to obtain modified graphene oxide;

[0022] A5. Add nanocellulose and chlorogenic acid-modified chitosan to deionized water, stir evenly, add sodium hydroxide, stir at 50 - 60 °C for 10 - 15 min, add modified graphene oxide and modified cellulose nanowhiskers, and continue to stir and react for 10 - 20 min to obtain enhanced filler.

[0023] Furthermore, during the reaction process of step A1, in Tris-HCl buffer, dopamine can self-polymerize on the surface of cellulose nanowhiskers to form polydopamine, forming polydopamine-modified cellulose nanowhiskers, making the cellulose nanowhiskers have good adhesiveness, which is beneficial to the formation of calcium carbonate particles on the surface of cellulose nanowhiskers.

[0024] Furthermore, during the reaction process of step A2, the phenolic hydroxyl groups contained on the surface of polydopamine-modified cellulose nanowhiskers can combine with calcium ions in calcium chloride, causing calcium ions to deposit on the surface of polydopamine-modified cellulose nanowhiskers. After introducing carbon dioxide and air, a carbonization reaction occurs, and calcium carbonate crystals can be formed on the surface of polydopamine-modified cellulose nanowhiskers. As the reaction progresses, the contained NH4 + can combine with the hydroxyl groups on the surface of calcium carbonate crystals, promoting the aggregation and growth of calcium carbonate crystals, realizing the formation of calcium carbonate particles on the surface of polydopamine-modified cellulose nanowhiskers, and obtaining modified cellulose nanowhiskers.

[0025] Furthermore, during the reaction in step A3, the oxygen-containing functional groups on the surface of graphene oxide can combine with aluminum ions in the aluminum nitrate solution, causing the aluminum hydroxide generated during the reaction to deposit on the surface of graphene oxide. After hydrothermal treatment, the aluminum hydroxide decomposes upon heating to form alumina crystals. As the reaction progresses, the alumina crystals grow, achieving the formation of nano-alumina on the surface of graphene oxide and obtaining graphene oxide loaded with nano-alumina.

[0026] Furthermore, during the reaction in step A4, octamethylcyclotetrasiloxane undergoes ring-opening polymerization under acid catalysis, and the terminal hydroxyl groups of the polysiloxane chain react with the hydroxyl groups on the surface of graphene oxide loaded with nano-alumina, causing octamethylcyclotetrasiloxane to graft onto the surface of graphene oxide loaded with nano-alumina, obtaining modified graphene oxide.

[0027] Furthermore, during the reaction in step A5, chlorogenic acid-modified chitosan and hydroxyethyl cellulose combine through hydrogen bonds to form a cross-linked network structure, and modified cellulose nanocrystals and modified graphene oxide are embedded in the cross-linked network structure to form a three-dimensional network structure bound by hydrogen bonds, obtaining a reinforcing filler.

[0028] Furthermore, in step A1, the dosage ratio of cellulose nanocrystals, Tris-HCl buffer solution, and dopamine is (1 - 2) g : (50 - 60) mL : (0.4 - 0.6) g.

[0029] Furthermore, in step A2, the dosage ratio of calcium chloride, deionized water, and polydopamine-modified cellulose nanocrystals is (7 - 9) g : (75 - 85) mL : (3 - 5) g.

[0030] Furthermore, in step A2, the volume ratio of carbon dioxide to air is (1 - 3) : (5 - 7).

[0031] Furthermore, in step A3, the dosage ratio of graphene oxide, aluminum nitrate solution, and urea is (4 - 5) g : (45 - 55) mL : (4 - 6) g.

[0032] Furthermore, in step A4, the dosage ratio of graphene oxide loaded with nano-alumina, deionized water, sulfuric acid, and octamethylcyclotetrasiloxane is (4 - 6) g : (20 - 30) mL : (4 - 6) mL : (1 - 1.4) g.

[0033] Furthermore, in step A5, the mass ratio of modified cellulose nanocrystals, modified graphene oxide, chlorogenic acid-modified chitosan, and hydroxyethyl cellulose is (2 - 4) : (3 - 5) : (8 - 10) : (10 - 12).

[0034] Furthermore, the concentration of the aluminum nitrate solution is 0.2 - 0.4 mol / L.

[0035] Furthermore, the hydrothermal reaction temperature is 140 - 160 °C, and the hydrothermal reaction time is 5 - 8 h.

[0036] Furthermore, the particle size of graphene oxide is 0.2 - 1 μm.

[0037] Furthermore, the cellulose nanocrystals are specifically prepared by the following steps:

[0038] Add microcrystalline cellulose into sulfuric acid solution, stir evenly, place it at 35 - 45 °C and stir for reaction for 1 - 3 h, add deionized water for dilution to end the reaction, separate, disperse the collected nanocrystals in deionized water, after dialysis treatment, freeze-dry to obtain cellulose nanocrystals.

[0039] Furthermore, the dosage ratio of microcrystalline cellulose to sulfuric acid solution is (5 - 7) g : (80 - 100) mL.

[0040] Furthermore, the chlorogenic acid-modified chitosan is specifically prepared by the following steps:

[0041] Add chitosan into acetic acid solution, stir evenly to obtain chitosan solution. Add chlorogenic acid, N-hydroxysuccinimide and 1-ethyl-(3-dimethylaminopropyl) carbodiimide hydrochloride into ethanol, stir and mix, then add it into chitosan solution. After stirring and reacting in an ice-water bath, centrifuge to collect the supernatant, and freeze-dry the supernatant to obtain chlorogenic acid-modified chitosan.

[0042] Furthermore, in the above reaction process, chlorogenic acid reacts with chitosan, and then grafts chlorogenic acid onto chitosan to obtain chlorogenic acid-modified chitosan.

[0043] Furthermore, the dosage ratio of chitosan, acetic acid solution, chlorogenic acid, N-hydroxysuccinimide, 1-ethyl-(3-dimethylaminopropyl) carbodiimide hydrochloride and ethanol is (1 - 3) g : (45 - 55) mL : (0.4 - 0.6) g : (0.1 - 0.3) g : (0.2 - 0.24) g : (18 - 22) mL.

[0044] Furthermore, compared with the prior art, the present invention has the following beneficial effects:

[0045] (1) In the technical solution of the present invention, the cellulose nanocrystals modified with polydopamine have good adhesiveness, which is beneficial to the formation of calcium carbonate particles on the surface of cellulose nanocrystals, enhancing the mechanical properties of the muck-based concrete; the formation of calcium carbonate particles on the surface of the polydopamine-modified cellulose nanocrystals, on the one hand, the formed nano-calcium carbonate particles can penetrate into the pores of the muck, improving the density of the muck and enhancing the mechanical properties of the muck, on the other hand, the cellulose nanocrystals can fill the micropores and cracks in the muck and, as a bridging structure, tightly connect the muck together, significantly improving the strength and durability of the muck. In addition, due to the excellent aspect ratio of the cellulose nanocrystals, their random distribution in the muck improves the impact resistance of the muck.

[0046] (2) In the technical solution of the present invention, the formation of nano-aluminum oxide on the surface of graphene oxide, on the one hand, the formation of nano-aluminum oxide on the surface of graphene oxide provides a large number of rough surfaces, increasing the contact area with the muck, making the graphene oxide loaded with nano-aluminum oxide tightly combined with the muck, and improving the mechanical properties of the muck. On the other hand, the formation of nano-aluminum oxide on the surface of graphene oxide can fill the pores as a nanomaterial, improving the density of the muck, which is beneficial to the transportation of the muck, and the formed muck-based concrete has high mechanical properties; octamethylcyclotetrasiloxane is grafted on the surface of the graphene oxide loaded with nano-aluminum oxide, and octamethylcyclotetrasiloxane can react with the organosilicon in the muck, thereby enhancing the binding force between the modified graphene oxide and the muck, further enhancing the density of the muck and improving the mechanical properties of the muck.

[0047] (3) In the technical solution of the present invention, chlorogenic acid is grafted onto chitosan, and then mixed with modified cellulose nanocrystals, modified graphene oxide and hydroxyethyl cellulose to form a three-dimensional network structure bound by hydrogen bonds, which plays a role in transmitting stress and further enhances the mechanical properties of the muck-based concrete. Moreover, chlorogenic acid-modified chitosan and hydroxyethyl cellulose, as the skeleton structure of the muck, can adsorb onto the surface of the muck, further enhancing the density of the muck and improving the mechanical properties. Specific embodiments

[0048] The technical solutions in the embodiments of the present invention are clearly and completely described. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0049] The raw materials used in the embodiments of the present invention are as follows, and all the reagents used are of analytical grade.

[0050] The hard rock tunneling muck is selected from the muck generated by the tunneling of a TBM (full-face rock tunneling machine).

[0051] The performance indicators of the muck from hard rock tunneling are shown in the following table:

[0052] Table 1

[0053]

[0054] The quicklime was purchased from Yangzhou Yongshun Purification Materials Co., Ltd., Jiangsu.

[0055] The particle size of graphene oxide is 0.5 μm.

[0056] Microcrystalline cellulose was from Shanghai Macklin Biochemical Co., Ltd.

[0057] The cellulose nanocrystals were specifically prepared by the following steps:

[0058] 6 g of microcrystalline cellulose was added to 90 mL of sulfuric acid solution with a mass fraction of 64%, stirred evenly, placed at 40 °C and stirred for 2 h, then 100 mL of deionized water was added for dilution to end the reaction. After separation, the collected nanocrystals were dispersed in 100 mL of deionized water, and after dialysis treatment, they were freeze-dried at -20 °C for 1 h to obtain cellulose nanocrystals.

[0059] The chlorogenic acid-modified chitosan was specifically prepared by the following steps:

[0060] 2 g of chitosan was added to 50 mL of acetic acid solution with a mass fraction of 2%, stirred evenly to obtain a chitosan solution. 0.5 g of chlorogenic acid, 0.2 g of N-hydroxysuccinimide and 0.22 g of 1-ethyl-(3-dimethylaminopropyl) carbodiimide hydrochloride were added to 20 mL of ethanol, stirred and mixed for 2 h, then added to the chitosan solution, stirred and reacted in an ice-water bath for 40 min, centrifuged at 10000 r / min for 20 min, and the supernatant was collected. The supernatant was freeze-dried at -20 °C for 20 min to obtain chlorogenic acid-modified chitosan.

[0061] The reinforcing filler in Example 1 was specifically prepared by the following steps:

[0062] A1. 1.5 g of cellulose nanocrystals was added to 55 mL of Tris-HCl buffer solution with a pH of 8.5, stirred evenly, 0.5 g of dopamine was added, stirred for 4 h, filtered, washed 3 times with deionized water, and dried in an oven at 70 °C for 10 min to obtain polydopamine-modified cellulose nanocrystals;

[0063] A2. Add 8 g of calcium chloride to 80 mL of deionized water, stir until completely dissolved, add 4 g of polydopamine-modified cellulose nanocrystalline whiskers, stir for 10 min, add ammonia water with a mass fraction of 30% to adjust the pH to 8, place it in a reaction kettle, and introduce 2 mL of carbon dioxide and 6 mL of air at a rate of 2.5 L / min. React at 30 °C for 2 h, filter to collect the solid, and dry the solid in an oven at 105 °C for 20 min to obtain modified cellulose nanocrystalline whiskers;

[0064] A3. Add 4.5 g of graphene oxide to 50 mL of aluminum nitrate solution with a concentration of 0.3 mol / L, stir evenly, add 5 g of urea, place it in a high-pressure kettle at 150 °C, carry out hydrothermal reaction for 6 h, cool to room temperature, filter to collect the gel, and calcine it at 550 °C for 2 h to obtain graphene oxide loaded with nano-aluminum oxide;

[0065] A4. Add 5 g of graphene oxide loaded with nano-aluminum oxide to 25 mL of deionized water, stir evenly, add 5 mL of sulfuric acid with a mass fraction of 3% and 1.2 g of octamethylcyclotetrasiloxane, heat up to 60 °C, stir and react for 3 h, cool to room temperature, filter, wash with deionized water 3 times, and dry in an oven at 70 °C for 10 min to obtain modified graphene oxide;

[0066] A5. Add 11 g of nanocellulose and 9 g of chlorogenic acid-modified chitosan to 20 mL of deionized water, stir evenly, add 7 g of sodium hydroxide, stir at 55 °C for 13 min, add 4 g of modified graphene oxide and 3 g of modified cellulose nanocrystalline whiskers, and continue to stir and react for 15 min to obtain the reinforcing filler.

[0067] Comparative Example 1 The difference between this comparative example and Example 1 is that the polydopamine-modified cellulose nanocrystalline whiskers are replaced with cellulose nanocrystalline whiskers, and the remaining steps and raw materials are the same as those in Example 1.

[0068] The reinforcing filler is specifically prepared by the following steps:

[0069] A1. Add 8 g of calcium chloride to 80 mL of deionized water, stir until completely dissolved, add 4 g of cellulose nanocrystalline whiskers, stir for 10 min, add ammonia water with a mass fraction of 30% to adjust the pH to 8, place it in a reaction kettle, and introduce 2 mL of carbon dioxide and 6 mL of air at a rate of 2.5 L / min. React at 30 °C for 2 h, filter to collect the solid, and dry the solid in an oven at 105 °C for 20 min to obtain modified cellulose nanocrystalline whiskers;

[0070] A2. Add 4.5 g of graphene oxide to 50 mL of an aluminum nitrate solution with a concentration of 0.3 mol / L, stir evenly, add 5 g of urea, place it in a high-pressure autoclave at 150 °C, carry out hydrothermal reaction for 6 h, cool to room temperature, filter and collect the gel, and calcine it at 550 °C for 2 h to obtain graphene oxide loaded with nano-aluminum oxide;

[0071] A3. Add 5 g of graphene oxide loaded with nano-aluminum oxide to 25 mL of deionized water, stir evenly, add 5 mL of sulfuric acid with a mass fraction of 3% and 1.2 g of octamethylcyclotetrasiloxane, heat up to 60 °C, stir and react for 3 h, cool to room temperature, filter, wash with deionized water 3 times, and dry in an oven at 70 °C for 10 min to obtain modified graphene oxide;

[0072] A4. Add 11 g of nanocellulose and 9 g of chlorogenic acid-modified chitosan to 20 mL of deionized water, stir evenly, add 7 g of sodium hydroxide, stir at 55 °C for 13 min, add 4 g of modified graphene oxide and 3 g of modified cellulose nanocrystals, and continue to stir and react for 15 min to obtain an enhanced filler.

[0073] Comparative Example 2 The difference between this comparative example and Example 1 is that the modified cellulose nanocrystals are replaced by polydopamine-modified cellulose nanocrystals, and the remaining steps and raw materials are the same as those in Example 1.

[0074] A1. Add 1.5 g of cellulose nanocrystals to 55 mL of Tris-HCl buffer solution with a pH of 8.5, stir evenly, add 0.5 g of dopamine, stir for 4 h, filter, wash with deionized water 3 times, and dry in an oven at 70 °C for 10 min to obtain polydopamine-modified cellulose nanocrystals;

[0075] A2. Add 4.5 g of graphene oxide to 50 mL of an aluminum nitrate solution with a concentration of 0.3 mol / L, stir evenly, add 5 g of urea, place it in a high-pressure autoclave at 150 °C, carry out hydrothermal reaction for 6 h, cool to room temperature, filter and collect the gel, and calcine it at 550 °C for 2 h to obtain graphene oxide loaded with nano-aluminum oxide;

[0076] A3. Add 5 g of graphene oxide loaded with nano-aluminum oxide to 25 mL of deionized water, stir evenly, add 5 mL of sulfuric acid with a mass fraction of 3% and 1.2 g of octamethylcyclotetrasiloxane, heat up to 60 °C, stir and react for 3 h, cool to room temperature, filter, wash with deionized water 3 times, and dry in an oven at 70 °C for 10 min to obtain modified graphene oxide;

[0077] A4. Add 11 g of nanocellulose and 9 g of chlorogenic acid-modified chitosan to 20 mL of deionized water, stir evenly, add 7 g of sodium hydroxide, stir at 55 °C for 13 min, add 4 g of modified graphene oxide and 3 g of polydopamine-modified cellulose nanocrystals, and continue to stir and react for 15 min to obtain the reinforcing filler.

[0078] Comparative Example 3 The difference between this comparative example and Example 1 is that the graphene oxide loaded with nanoaluminum oxide is replaced by graphene oxide, and the remaining steps and raw materials are the same as those in Example 1.

[0079] The reinforcing filler is specifically prepared by the following steps:

[0080] A1. Add 1.5 g of cellulose nanocrystals to 55 mL of Tris-HCl buffer solution with a pH of 8.5, stir evenly, add 0.5 g of dopamine, stir for 4 h, filter, wash with deionized water 3 times, and dry in an oven at 70 °C for 10 min to obtain polydopamine-modified cellulose nanocrystals;

[0081] A2. Add 8 g of calcium chloride to 80 mL of deionized water, stir until completely dissolved, add 4 g of polydopamine-modified cellulose nanocrystals, stir for 10 min, add ammonia water with a mass fraction of 30% to adjust the pH to 8, place it in a reaction kettle, and pass 2 mL of carbon dioxide and 6 mL of air at a rate of 2.5 L / min, react at 30 °C for 2 h, filter and collect the solid, and dry the solid in an oven at 105 °C for 20 min to obtain modified cellulose nanocrystals;

[0082] A3. Add 5 g of graphene oxide to 25 mL of deionized water, stir evenly, add 5 mL of sulfuric acid with a mass fraction of 3% and 1.2 g of octamethylcyclotetrasiloxane, heat up to 60 °C, stir and react for 3 h, cool to room temperature, filter, wash with deionized water 3 times, and dry in an oven at 70 °C for 10 min to obtain modified graphene oxide;

[0083] A4. Add 11 g of nanocellulose and 9 g of chlorogenic acid-modified chitosan to 20 mL of deionized water, stir evenly, add 7 g of sodium hydroxide, stir at 55 °C for 13 min, add 4 g of modified graphene oxide and 3 g of modified cellulose nanocrystals, and continue to stir and react for 15 min to obtain the reinforcing filler.

[0084] Comparative Example 4 The difference between this comparative example and Example 1 is that the modified graphene oxide is replaced by graphene oxide loaded with nanoaluminum oxide, and the remaining steps and raw materials are the same as those in Example 1.

[0085] The reinforcing filler is specifically prepared by the following steps:

[0086] A1. Add 1.5 g of cellulose nanowhiskers to 55 mL of Tris-HCl buffer with a pH of 8.5, stir evenly, add 0.5 g of dopamine, stir for 4 h, filter, wash with deionized water 3 times, and dry in an oven at 70 °C for 10 min to obtain polydopamine-modified cellulose nanowhiskers;

[0087] A2. Add 8 g of calcium chloride to 80 mL of deionized water, stir until completely dissolved, add 4 g of polydopamine-modified cellulose nanowhiskers, stir for 10 min, add ammonia water with a mass fraction of 30% to adjust the pH to 8, place in a reaction kettle, and introduce 2 mL of carbon dioxide and 6 mL of air at a rate of 2.5 L / min. React at 30 °C for 2 h, filter to collect the solid, and dry the solid in an oven at 105 °C for 20 min to obtain modified cellulose nanowhiskers;

[0088] A3. Add 4.5 g of graphene oxide to 50 mL of aluminum nitrate solution with a concentration of 0.3 mol / L, stir evenly, add 5 g of urea, place in a high-pressure kettle at 150 °C, carry out hydrothermal reaction for 6 h, cool to room temperature, filter to collect the gel, and calcine at 550 °C for 2 h to obtain graphene oxide loaded with nano-aluminum oxide;

[0089] A4. Add 11 g of nanocellulose and 9 g of chlorogenic acid-modified chitosan to 20 mL of deionized water, stir evenly, add 7 g of sodium hydroxide, stir at 55 °C for 13 min, add 4 g of graphene oxide loaded with nano-aluminum oxide and 3 g of modified cellulose nanowhiskers, and continue to stir and react for 15 min to obtain the reinforcing filler.

[0090] Comparative Example 5 The difference between this comparative example and Example 1 is that nanocellulose and chlorogenic acid-modified chitosan are not added, and the remaining steps and raw materials are the same as those in Example 1.

[0091] The reinforcing filler is specifically prepared by the following steps:

[0092] A1. Add 1.5 g of cellulose nanowhiskers to 55 mL of Tris-HCl buffer with a pH of 8.5, stir evenly, add 0.5 g of dopamine, stir for 4 h, filter, wash with deionized water 3 times, and dry in an oven at 70 °C for 10 min to obtain polydopamine-modified cellulose nanowhiskers;

[0093] A2. Add 8 g of calcium chloride to 80 mL of deionized water, stir until completely dissolved, add 4 g of cellulose nanocrystals modified with polydopamine, stir for 10 min, add ammonia water with a mass fraction of 30% to adjust the pH to 8, place it in a reaction kettle, and introduce 2 mL of carbon dioxide and 6 mL of air at a rate of 2.5 L / min. React at 30 °C for 2 h, filter to collect the solid, and dry the solid in an oven at 105 °C for 20 min to obtain modified cellulose nanocrystals;

[0094] A3. Add 4.5 g of graphene oxide to 50 mL of aluminum nitrate solution with a concentration of 0.3 mol / L, stir evenly, add 5 g of urea, place it in a high-pressure kettle at 150 °C, carry out hydrothermal reaction for 6 h, cool to room temperature, filter to collect the gel, and calcine at 550 °C for 2 h to obtain graphene oxide loaded with nano-aluminum oxide;

[0095] A4. Add 5 g of graphene oxide loaded with nano-aluminum oxide to 25 mL of deionized water, stir evenly, add 5 mL of sulfuric acid with a mass fraction of 3% and 1.2 g of octamethylcyclotetrasiloxane, heat up to 60 °C, stir and react for 3 h, cool to room temperature, filter, wash with deionized water 3 times, and dry in an oven at 70 °C for 10 min to obtain modified graphene oxide;

[0096] A5. Add 20 mL of deionized water, 7 g of sodium hydroxide, 4 g of modified graphene oxide and 3 g of modified cellulose nanocrystals, and stir at 55 °C for 15 min to obtain an enhanced filler.

[0097] Example 2 A process method for resource improvement of hard rock tunneling muck, including the following steps:

[0098] S1. Mix the hard rock tunneling muck with quicklime, stir evenly, cover and stuff for 8 h, crush and screen to obtain pretreated muck;

[0099] S2. Mix the pretreated muck, powder soil solidifying agent and the enhanced filler prepared in Example 1, stir and mix at a rate of 500 r / min for 30 min, crush and screen to obtain resource-improved muck;

[0100] Among them, the mass ratio of hard rock tunneling muck to quicklime is 80:5;

[0101] The mass ratio of the pretreated muck, the powder soil solidifying agent and the enhanced filler prepared in Example 1 is 80:4:8;

[0102] The powder soil solidifying agent is composed of sodium methyl silicate, sodium alginate, sodium dodecyl benzene sulfonate, sodium chloride, lithium hydroxide and polycarboxylate superplasticizer mixed according to a mass ratio of 3:0.6:1:0.8:0.1:0.2.

[0103] Example 3 A resource improvement process method for hard rock tunneling muck, comprising the following steps:

[0104] S1. Mix the hard rock tunneling muck with quicklime, stir evenly, cover and let it sit for 10 h, then crush and screen it to obtain pre-treated muck.

[0105] S2. Mix the pre-treated muck, powder soil stabilizer and the strengthening filler prepared in Example 1, stir and mix at a rate of 550 r / min for 35 min, then crush and screen it to obtain resource-improved muck.

[0106] Wherein, the mass ratio of the hard rock tunneling muck to quicklime is 90:6.

[0107] The mass ratio of the pre-treated muck, powder soil stabilizer and the strengthening filler prepared in Example 1 is 90:5:9.

[0108] The powder soil stabilizer is prepared by mixing sodium methyl silicate, sodium alginate, sodium dodecyl benzene sulfonate, sodium chloride, lithium hydroxide and polycarboxylate superplasticizer in a mass ratio of 4:0.8:1.3:1:0.2:0.3.

[0109] Example 4 A resource improvement process method for hard rock tunneling muck, comprising the following steps:

[0110] S1. Mix the hard rock tunneling muck with quicklime, stir evenly, cover and let it sit for 12 h, then crush and screen it to obtain pre-treated muck.

[0111] S2. Mix the pre-treated muck, powder soil stabilizer and the strengthening filler prepared in Example 1, stir and mix at a rate of 600 r / min for 40 min, then crush and screen it to obtain resource-improved muck.

[0112] Wherein, the mass ratio of the hard rock tunneling muck to quicklime is 100:7.

[0113] The mass ratio of the pre-treated muck, powder soil stabilizer and the strengthening filler prepared in Example 1 is 100:6:10.

[0114] The powder soil stabilizer is prepared by mixing sodium methyl silicate, sodium alginate, sodium dodecyl benzene sulfonate, sodium chloride, lithium hydroxide and polycarboxylate superplasticizer in a mass ratio of 5:1:1.5:1.2:0.3:0.4.

[0115] Comparative Example 6 The difference between this comparative example and Example 3 is that the strengthening filler prepared in Example 1 is replaced with the substance prepared in Comparative Example 1, and the remaining steps are the same as those in Example 3.

[0116] Comparative Example 7 The difference between this comparative example and Example 3 is that the reinforcing filler prepared in Example 1 is replaced with the substance prepared in Comparative Example 2, and the remaining steps are the same as those in Example 3.

[0117] Comparative Example 8 The difference between this comparative example and Example 3 is that the reinforcing filler prepared in Example 1 is replaced with the substance prepared in Comparative Example 3, and the remaining steps are the same as those in Example 3.

[0118] Comparative Example 9 The difference between this comparative example and Example 3 is that the reinforcing filler prepared in Example 1 is replaced with the substance prepared in Comparative Example 4, and the remaining steps are the same as those in Example 3.

[0119] Comparative Example 10 The difference between this comparative example and Example 3 is that the reinforcing filler prepared in Example 1 is replaced with the substance prepared in Comparative Example 5, and the remaining steps are the same as those in Example 3.

[0120] Now, the performance of the resource-improved muck prepared in Examples 2-4 and Comparative Examples 6-10 was tested.

[0121] The unconfined compressive strength of the above-prepared resource-improved muck after 7 days and 28 days was tested using a strain-controlled unconfined compression apparatus.

[0122] The measured data are shown in Table 2 below:

[0123] Table 2

[0124]

[0125]

[0126] As can be seen from the data in Table 2, when the reinforcing filler prepared by replacing the polydopamine-modified cellulose nanowhiskers with cellulose nanowhiskers in Comparative Example 6 was added to the resource-improved muck to prepare concrete, the mechanical properties of the concrete decreased. This may be because the polydopamine-modified cellulose nanowhiskers endow the cellulose nanowhiskers with good adhesion, which is conducive to the formation of calcium carbonate particles on the surface of the cellulose nanowhiskers, enhancing the mechanical properties of the muck-based concrete. In Comparative Example 6, there is a lack of polydopamine on the surface of the cellulose nanowhiskers, so the mechanical properties of the prepared muck-based concrete decreased.

[0127] In Comparative Example 7, when the modified cellulose nanowhiskers were replaced with the reinforcing filler prepared by polydopamine-modified cellulose nanowhiskers and added to the resource-improved muck to prepare concrete, the mechanical properties of the concrete decreased. This may be because calcium carbonate particles are formed on the surface of the polydopamine-modified cellulose nanowhiskers, and the formed nano-calcium carbonate particles can penetrate into the pores of the muck, improving the density of the muck and enhancing the mechanical properties of the muck. In Comparative Example 7, there is a lack of polycalcium carbonate particles on the surface of the polydopamine-modified cellulose nanowhiskers, so the mechanical properties of the prepared muck-based concrete decreased.

[0128] Comparative Example 8: The graphene oxide without loaded nano-aluminum oxide was used as the reinforcing filler and added to the resource-improved muck to prepare concrete. The mechanical properties of the prepared concrete decreased. This may be because nano-aluminum oxide is formed on the surface of graphene oxide, providing a large number of rough surfaces and increasing the contact area with the muck, so that the graphene oxide loaded with nano-aluminum oxide is tightly combined with the muck, improving the mechanical properties of the muck. However, there is no nano-aluminum oxide on the surface of graphene oxide in Comparative Example 8, so the mechanical properties of the muck-based concrete prepared decrease.

[0129] Comparative Example 9: The modified graphene oxide was replaced by the graphene oxide loaded with nano-aluminum oxide as the reinforcing filler and added to the resource-improved muck to prepare concrete. The mechanical properties of the prepared concrete decreased. This may be because octamethylcyclotetrasiloxane is grafted on the surface of the graphene oxide loaded with nano-aluminum oxide. Octamethylcyclotetrasiloxane can react with the organosilicon in the muck, thereby enhancing the binding force between the modified graphene oxide and the muck, further enhancing the compactness of the muck and improving the mechanical properties of the muck. However, there is no octamethylcyclotetrasiloxane on the surface of the graphene oxide loaded with nano-aluminum oxide in Comparative Example 9, so the mechanical properties of the muck-based concrete prepared decrease.

[0130] Comparative Example 10: The reinforcing filler prepared without adding nano-cellulose and chitosan modified by chlorogenic acid was added to the resource-improved muck to prepare concrete. The mechanical properties of the prepared concrete decreased. This may be because chitosan modified by chlorogenic acid and hydroxyethyl cellulose, as the skeleton structure of the muck, can be adsorbed on the surface of the muck, further enhancing the compactness of the muck and improving the mechanical properties. Moreover, the modified cellulose nanocrystals and the modified graphene oxide are embedded in the structure of chitosan modified by chlorogenic acid and hydroxyethyl cellulose to form a three-dimensional network structure capable of transmitting stress, further enhancing the mechanical properties of the muck-based concrete.

[0131] The data in Table 2 show that the resource-improved muck prepared in Examples 2-4 meets the requirements of the test performance, while the resource-improved muck prepared in Comparative Examples 6-10 does not meet the performance requirements, indicating that the resource-improved muck prepared by the present invention has good mechanical properties and compactness.

[0132] In the description of the specification, the description referring to terms such as "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0133] The above content is only an example and illustration of the present invention. Those skilled in the art to which the present technology pertains can make various modifications or supplements to the described specific embodiments, or use similar methods for substitution. As long as they do not deviate from the invention or exceed the scope defined by the claims of the present invention, they shall fall within the protection scope of the present invention.

Claims

1. An improved process for recycling hard rock excavation waste, characterized in that: The following steps are involved: S1. Mix the hard rock excavation soil with the dehydrating agent, stir evenly, cover and stew for 8-12h, crush, stir and mix to obtain pre-treated soil; S2. The pretreated slag, the powdered soil curing agent and the reinforcing filler are mixed, stirred and mixed at a rate of 500-600r / min for 30-40min, and the slag is crushed, stirred and mixed to obtain resource-based improved slag; The reinforcing filler is obtained by mixing and reacting modified cellulose nano whiskers, modified graphene oxide, chlorogenic acid-modified chitosan and hydroxyethyl cellulose; The modified cellulose nano whiskers are obtained by modifying the surface of cellulose nano whiskers with polydopamine and then in-situ depositing calcium carbonate particles; The modified graphene oxide is obtained by mixing graphene oxide, aluminum nitrate solution and urea, performing a hydrothermal reaction, and then reacting with octamethylcyclotetrasiloxane.

2. The improved process for recycling hard rock excavation waste according to claim 1 is characterized in that: The dehydrating agent is quicklime, and the mass ratio of hard rock excavation waste to the dehydrating agent is (80-100):(5-7).

3. The improved process for recycling hard rock excavation waste according to claim 1 is characterized in that: The mass ratio of the pretreated slag, the powdered soil solidifying agent and the reinforcing filler is (80-100):(4-6):(8-10); The powder soil solidifier is prepared by mixing sodium methyl silicate, sodium alginate, sodium dodecylbenzene sulfonate, sodium chloride, lithium hydroxide and polycarboxylic acid high-efficiency water reducing agent in a mass ratio of (3-5):(0.6-1):(1-1.5):(0.8-1.2):(0.1-0.3):(0.2-0.4).

4. The improved process for recycling hard rock excavation waste according to claim 1 is characterized in that: The concentration of the aluminum nitrate solution is 0.2-0.4 mol / L; the hydrothermal reaction temperature is 140-160° C., and the hydrothermal reaction time is 5-8 hours.

5. The improved process for recycling hard rock excavation waste according to claim 1 is characterized in that: The graphene oxide particle size is 0.2-1 μm.

6. The improved process for recycling hard rock excavation waste according to claim 1 is characterized in that: The cellulose nano whiskers are specifically prepared by the following steps: Add microcrystalline cellulose to sulfuric acid solution, stir evenly, place at 35-45°C for stirring and reacting for 1-3 hours, add deionized water to dilute and terminate the reaction, separate and collect nano whiskers dispersed in deionized water, dialyze and freeze-dry to obtain cellulose nano whiskers.

7. The improved process for recycling hard rock excavation waste according to claim 6 is characterized in that: The dosage ratio of the microcrystalline cellulose and the sulfuric acid solution is (5-7) g: (80-100) mL.

8. The improved process for recycling hard rock excavation waste according to claim 1 is characterized in that: The chlorogenic acid modified chitosan is specifically prepared by the following steps: Add chitosan to acetic acid solution and stir evenly to obtain chitosan solution; add chlorogenic acid, N-hydroxysuccinimide and 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride to ethanol, stir and mix, and then add to the chitosan solution. After stirring in an ice water bath for reaction, collect the supernatant by centrifugation, and freeze-dry the supernatant to obtain chlorogenic acid-modified chitosan.

9. The improved process for recycling hard rock excavation waste according to claim 8, characterized in that: The amount ratio of chitosan, acetic acid solution, chlorogenic acid, N-hydroxysuccinimide, 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and ethanol is (1-3) g: (45-55) mL: (0.4-0.6) g: (0.1-0.3) g: (0.2-0.24) g: (18-22) mL.

10. The improved process for recycling hard rock excavation waste according to claim 1, characterized in that: The mass ratio of the modified cellulose nano whiskers, modified graphene oxide, chlorogenic acid modified chitosan and hydroxyethyl cellulose is (2-4):(3-5):(8-10):(10-12).

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