Ma et al 2024a - Revision history

Rimni at 10:23, 13 June 2024

2024-06-13T10:23:04Z

Rimni at 10:21, 13 June 2024

2024-06-13T10:21:03Z

Rimni: /* References */

2024-06-12T11:42:28Z

‎References

Rimni at 10:43, 12 June 2024

2024-06-12T10:43:33Z

Rimni at 09:19, 12 June 2024

2024-06-12T09:19:28Z

Rimni at 09:03, 12 June 2024

2024-06-12T09:03:26Z

Rimni at 08:59, 12 June 2024

2024-06-12T08:59:00Z

Rimni at 08:58, 12 June 2024

2024-06-12T08:58:16Z

Rimni: /* 3. Numerical modeling */

2024-06-12T08:56:20Z

‎3. Numerical modeling

Rimni at 08:55, 12 June 2024

2024-06-12T08:55:41Z

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 {| class="wikitable" style="margin: 0em auto 0.1em auto;border-collapse: collapse;width:auto;"
 |-style="background:white;"
-|style="text-align: center;padding:10px;"| [[Image:Review_826582983555-image11.png|372px]]
+|style="text-align: center;padding:10px;"| [[Image:Review_826582983555-image11.png|472px]]
 |-
 | style="background:#efefef;text-align:left;padding:10px;font-size: 85%;"| '''Figure 9'''. Reduction rate of horizontal displacement in Cases II-V

← Older revision		Revision as of 10:21, 13 June 2024
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−	The rock surrounding the tunnel is Grade VI, which is extremely unstable. In addition, the tunnel entrance passes through a landslide, which can cause significant safety hazards such as surface settlement, collapse and landslide recovery during excavation. The middle partition method can be used to place support structures in the centre of the tunnel to provide additional support and protection, effectively controlling surface settlement and reducing the risk of rock collapse. The middle partition method involved the following sequence: (1) Part A is excavated first with temporary support in place. (2) Excavation of both Parts A and B simultaneously after excavating Part A for 2 m, with temporary support in place for both Part A and Part B. (3) Excavation of parts A, B, and C simultaneously after excavating parts B for 2 m, with temporary support in place for all three parts; (4) Excavation of parts A, B, C, and D simultaneously after excavating parts C for 2 m, with temporary support in place for all four parts. This excavation process continues in a cyclic manner, typically with each part being excavated in a sequence of 1 m at a time.	+	The rock surrounding the tunnel is Grade VI, which is extremely unstable. In addition, the tunnel entrance passes through a landslide, which can cause significant safety hazards such as surface settlement, collapse and landslide recovery during excavation. The middle partition method can be used to place support structures in the centre of the tunnel to provide additional support and protection, effectively controlling surface settlement and reducing the risk of rock collapse. The middle partition method involved the following sequence: (1) Part A is excavated first with temporary support in place. (2) Excavation of both Parts A and B simultaneously after excavating Part A for 2 m, with temporary support in place for both Part A and Part B. (3) Excavation of parts A, B, and C simultaneously after excavating parts B for 2 m, with temporary support in place for all three parts. (4) Excavation of parts A, B, C, and D simultaneously after excavating parts C for 2 m, with temporary support in place for all four parts. This excavation process continues in a cyclic manner, typically with each part being excavated in a sequence of 1 m at a time.

	==3. Numerical modeling==		==3. Numerical modeling==

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 ==References==
-[1] Adam D., Markiewicz R., Brunner M., Block-in-matrix structure and creeping slope: tunneling in hard soil and/or weak rock. Geotechnical & Geological Engineering, 32: 1467 – 1476, 2014.
+[1] Adam D., Markiewicz R., Brunner M., Block-in-matrix structure and creeping slope: tunneling in hard soil and/or weak rock. Geotechnical & Geological Engineering, 32:1467–1476, 2014.
-[2] Zhang Q., Wang J., Wang W., et al. Study on slope stability due to the influence of excavation of the high-speed rail tunnel. Geomatics, Natural Hazards Risk, 10(1): 1193 – 1208, 2019.
+[2] Zhang Q., Wang J., Wang W., et al. Study on slope stability due to the influence of excavation of the high-speed rail tunnel. Geomatics, Natural Hazards Risk, 10(1):1193–1208, 2019.
-[3] Qin Y,W., Chen Y,H., Lai J,X., et al. Failures in loess slope-tunnel system: An overview of trigging sources, acting mechanism and mitigation strategies. Engineering Failure Analysis, 158107996, 2024.
+[3] Qin Y.W., Chen Y.H., Lai J.X., et al. Failures in loess slope-tunnel system: An overview of trigging sources, acting mechanism and mitigation strategies. Engineering Failure Analysis, 158, 107996, 2024.
-[4] Chen H., Lai H,P., Huang M., et al. Failure mechanism and treatment measures of supporting structures at the portal for a shallow buried and asymmetrically loaded tunnel with small clear-distance. Natural Hazards, 114(2): 2283 – 2310, 2022.
+[4] Chen H., Lai H.P., Huang M., et al. Failure mechanism and treatment measures of supporting structures at the portal for a shallow buried and asymmetrically loaded tunnel with small clear-distance. Natural Hazards, 114(2):2283–2310, 2022.
-[5] Guo J.C., Li C., Analysis of the Construction Plan for Entering the Mountain Tunnel. Railway Engineering, (10): 32 – 34, 2004. (''in Chinese'').
+[5] Guo J.C., Li C., Analysis of the construction plan for entering the mountain tunnel (in Chinese). Railway Engineering, (10):32–34, 2004.
-[6] Wang H.T., Jia J.Q., Kang H.G. Analytical approach and field monitoring for mechanical behaviors of pipe roof reinforcement. Journal of Central South University of Technology, 2009, 16(5): 827 – 834.
+[6] Wang H.T., Jia J.Q., Kang H.G. Analytical approach and field monitoring for mechanical behaviors of pipe roof reinforcement. Journal of Central South University of Technology, 16(5):827–834, 2009.
-[7] Bao L.L., Wei F., Tunnel construction in shallow soft rock using the pipe shed support. Scientific reports, 2024, 14(1): 3401 – 3401.
+[7] Bao L.L., Wei F. Tunnel construction in shallow soft rock using the pipe shed support. Scientific Reports, 14(1):3401–3401, 2024.
-[8] Shi Y.F., Zhang T., Cao C.W., et al. Study on the Mechanism of Tunnel Subhorizontal Jet Grouting Reinforcement Based on a Shell Model on Two-Parameter Foundation. Journal of Engineering Mechanics, 2024, 150(4).
+[8] Shi Y.F., Zhang T., Cao C.W., et al. Study on the mechanism of tunnel subhorizontal jet grouting reinforcement based on a shell model on two-parameter foundation. Journal of Engineering Mechanics, 150(4), 2024.
-[9] Cai M., Xu H., Han F.Q., et al. Analysis and Field Monitoring on Surface High Pressure Jet Grouting Reinforcement in Shallow-buried Tunnel Section. Journal of Highway and Transportation Research and Development, 2023, 40(01): 152 – 159.
+[9] Cai M., Xu H., Han F.Q., et al. Analysis and field monitoring on surface high pressure jet grouting reinforcement in shallow-buried tunnel section. Journal of Highway and Transportation Research and Development, 40(01):152–159, 2023.
-[10] Xiao J,Z., Dai F,C., Wei Y,Q., et al. Analysis of mechanical behavior in a pipe roof during excavation of a shallow bias tunnel in loose deposits. Environ. Earth Sci, 75 (4): 293, 2016.
+[10] Xiao J.Z., Dai F.C., Wei Y.Q., et al. Analysis of mechanical behavior in a pipe roof during excavation of a shallow bias tunnel in loose deposits. Environ. Earth Sci, 75(4), 293, 2016.
-[11] Ibtissem S., Mustapha A., Panagiotis S. Effect of the Umbrella Arch Technique Modelled as a Homogenized Area above a Cross Passage. Applied Sciences, 2023, 13(3): 1588 – 1588.
+[11] Ibtissem S., Mustapha A., Panagiotis S. Effect of the umbrella arch technique modelled as a homogenized area above a cross passage. Applied Sciences, 13(3):1588–1588, 2023.
-[12] Ying H.F., Wang L.Y., Ye H., et al Layout Optimization of Advance Reinforcement of Soft Rock Tunnel and Stratum Mechanical Response. Highway. 2022, 67(06): 378 – 385. (''in Chinese'').
+[12] Ying H.F., Wang L.Y., Ye H., et al Layout optimization of advance reinforcement of soft rock tunnel and stratum mechanical response (in Chinese). Highway, 67(06):378–385, 2022.
-[13] Xu J.S., Xu H., Zhang H.T., et al. Reinforcement mechanism and parameter analysis of horizontal high-pressure rotary jet grouting piles for Tertiary semi-diagenetic water-rich sandstone tunnel. Chinese Journal of Geotechnical Engineering. 2024, 1-10. (''in Chinese'').
+[13] Xu J.S., Xu H., Zhang H.T., et al. Reinforcement mechanism and parameter analysis of horizontal high-pressure rotary jet grouting piles for Tertiary semi-diagenetic water-rich sandstone tunnel (in Chinese). Chinese Journal of Geotechnical Engineering, 1-10, 2024.
-[14] JTG D70-2018. Specifications for Design of Highway Tunnels: Section 1 Civil Engineering. China Communication Press, Beijing, 91 – 96, 2018. (''in Chinese'').
+[14] JTG D70-2018. Specifications for design of highway tunnels: Section 1 Civil Engineering (in Chinese). China Communication Press, Beijing, 91–96, 2018.
-[15] Tang J,S., Liu S,Y., Tong L,Y. The minimum safe net dis-tance between large span expressway tunnels. China Civ. Eng. 41 (12): 79 – 84, 2008. (''in Chinese'').
+[15] Tang J,S., Liu S,Y., Tong L,Y. The minimum safe net dis-tance between large span expressway tunnels (in Chinese). China Civ. Eng., 41(12):79–84, 2008.
-[16] Xiao J,Z., Dai F,C., Wei Y,Q., et al. Cracking mechanism of secondary lining for a shallow and asymmetrically-loaded tunnel in loose deposits. Tunnelling Under-ground Space Technol. 43 (7): 232 – 240, 2014.
+[16] Xiao J.Z., Dai F.C., Wei Y.Q., et al. Cracking mechanism of secondary lining for a shallow and asymmetrically-loaded tunnel in loose deposits. Tunnelling Underground Space Technol., 43(7):232–240, 2014.

@@ Line 240: / Line 240: @@
 |}
-==4.3 Reinforcement effect of pre-supports on tunnel==
+===4.3 Reinforcement effect of pre-supports on tunnel===
-[[Image:Review_826582983555-image13.png|450px]]
+Take the key points B-F marked in [[#img-11|Figure 11]] and analyse the displacement changes of key points in different cases, where Sections 1-4 correspond to the sections of the tunnel where key points A1-A4 are located. There is almost no difference in the displacement of all key points in Cases I and II, indicating that the anti-slide pile has a relatively small control effect on the deformation of the tunnel structure. In the arch area (Key points B, C and I), the displacement of the key points shows a consistent pattern in all cross sections. The displacement of key points in Cases III, IV and V is highest in Cases III and lowest in Cases V, and these values are significantly smaller than in Cases I. This indicates that pre-supports can significantly improve the deformation of the rock surrounding the arch throughout the tunnel excavation process, and that the effect of the pipe roof is better than that of surface grouting. In the side wall area of the tunnel (Key points D and H), pre-supports still have a good deformation control effect in the entrance area. For example, in Section A1 the displacement was reduced by 35.4%, 35.9% and 59.6% in Cases III, IV and V. However, in Sections A2-A4, the effect of pre-support is not significant. Due to the fact that the tunnel in this paper is mainly affected by shallow burial and landslides, the deformation of the bottom area (Key points E, F and G) is very small even without pre-support (Cases I), so that targeted pre-supports are not necessary.
-'''Fig. 11 Displacement diagram of key points in tunnel section under different working conditions (unit: mm)'''
+<div id='img-11'></div>
 Along the direction of the tunnel axis, it can be seen that the deformation of all key points in Sections A1-A4 has decreased, especially in areas of large deformation such as arches and side walls. For example, the displacement of key point B in section 1-4 under condition 1 is 14.4 cm, 11.7 cm, 8.8 cm and 3.7 cm respectively, and the displacement in section 1-4 under condition 4 is 4.0 cm, 3.4 cm, 1.7 cm and 0.65 cm respectively. This indicates that the deformation of the tunnel structure is maximum in the early stages of excavation and that the tunnel becomes increasingly stable as excavation progresses.

@@ Line 213: / Line 213: @@
 The horizontal displacement reduction of the three key points A7-A9 is not significantly different due to the surface grouting being applied for a total of 60 m in the direction of the tunnel. Similarly, the vertical displacement reduction of the five key points A5-A9 is not significantly different as the pipe shed was applied for 40 m. It is crucial to establish appropriate dimensions for the pipe shed and surface grouting range when dealing with landslide mass. Analysis of Case I reveals that pre-support is necessary to prevent significant horizontal displacement of key points A7-A9, while the vertical displacement of key points A5-A9 remains within a small range (<10mm). This demonstrates that the original pre-supports design of the reinforcement range for surface grouting and the length of the pipe roofs is reasonably appropriate.
-==4.2 Reinforcement effect of multiple pre-supports on landslide==
+===4.2 Reinforcement effect of multiple pre-supports on landslide===
-Contrary to the deformation of the slope after a single pre-support, the maximum deformation of the slope in Case V (Fig. 6) is located at the upper edge, outside the area of surface grouting and pipe shed reinforcement, with a value of approximately 5.5 cm (a decrease of 63.6% compared to Case I). The deformation at the entrance of the landslide is relatively small, indicating that the mass of the landslide was well controlled under the combined action of the three pre-supports.
+Contrary to the deformation of the slope after a single pre-support, the maximum deformation of the slope in Case V ([[#img-6|Figure 6]]) is located at the upper edge, outside the area of surface grouting and pipe shed reinforcement, with a value of approximately 5.5 cm (a decrease of 63.6% compared to Case I). The deformation at the entrance of the landslide is relatively small, indicating that the mass of the landslide was well controlled under the combined action of the three pre-supports.
-The displacement changes of key points A1-A9 in Case V, as shown in Figs. 7 and 8, are consistent with the variation patterns observed in other cases. However, the deformation values are smaller than those in other cases. To compare the effect of multiple pre-supports and single pre-support, the reduction rate of horizontal displacement of each key point in Cases II-V was calculated.
+The displacement changes of key points A1-A9 in Case V, as shown in [[#img-7|Figures 7]] and [[#img-8|8]], are consistent with the variation patterns observed in other cases. However, the deformation values are smaller than those in other cases. To compare the effect of multiple pre-supports and single pre-support, the reduction rate of horizontal displacement of each key point in Cases II-V was calculated.
-The results presented in Fig. 9 illustrate that the reduction rate of horizontal displacement at each key point in Case V is basically equal to the sum of the corresponding reduction rates of horizontal displacement at key points in Cases II-IV. Specifically, the displacement reduction rate of key point A1 in Case V is 67.6%, while the displacement reduction rates in Cases II-IV are 4.8%, 40.8%, and 20.5%, respectively (the sum of which is 66.1%). The reinforcement effect of a single pre-support is not diminished when all three pre-supports are applied together. This is because the reinforcement mechanisms and scope of the three pre-supports are different, as discussed in section 4.1. Therefore, the effectiveness of a single pre-support is not reduced by multiple pre-supports.
+The results presented in [[#img-9|Figure 9]] illustrate that the reduction rate of horizontal displacement at each key point in Case V is basically equal to the sum of the corresponding reduction rates of horizontal displacement at key points in Cases II-IV. Specifically, the displacement reduction rate of key point A1 in Case V is 67.6%, while the displacement reduction rates in Cases II-IV are 4.8%, 40.8%, and 20.5%, respectively (the sum of which is 66.1%). The reinforcement effect of a single pre-support is not diminished when all three pre-supports are applied together. This is because the reinforcement mechanisms and scope of the three pre-supports are different, as discussed in section 4.1. Therefore, the effectiveness of a single pre-support is not reduced by multiple pre-supports.
-[[Image:Review_826582983555-image11.png|372px]]
+<div id='img-9'></div>
-[[Image:Review_826582983555-image12.png|414px]]
+[[#img-10|Figure 10]] shows the maximum principal stress for Case IV, where only the pipe roof is applied, and Case V, where three pre-supports are constructed simultaneously. The stress distribution characteristics between the two cases are similar, with only numerical differences. The maximum principal stress for the pipe roof in Cases IV and V are 62.7 MPa and 47.6 MPa, respectively. The minimum principal stresses in these two cases are 12.2 MPa and 8.3 MPa, respectively. It is obvious that under the combined action of the three types of pre-supports, the stress it bears is less than that of the pipe roof support alone. This is due to the interaction of the three types of pre-supports in Case V. Although the pipe roof can only provide local constraint in a limited area around it, the surface grouting increases the overall stiffness and strength of the surrounding rock. In addition, the anti-slide piles also prevent the landslide from recovering to some extent. Under the combined effect of the three types of pre-supports, the excavation area will be more stable and the support structure will be safer.
-'''Fig. 10 Maximum principal stress of pipe roof in Case IV and V (unit: Pa)'''
+<div id='img-1'></div>
+{| class="wikitable" style="margin: 0em auto 0.1em auto;border-collapse: collapse;width:auto;"
-Fig. 10 shows the maximum principal stress for Case IV, where only the pipe roof is applied, and Case V, where three pre-supports are constructed simultaneously. The stress distribution characteristics between the two cases are similar, with only numerical differences. The maximum principal stress for the pipe roof in Cases IV and V are 62.7 MPa and 47.6 MPa, respectively. The minimum principal stresses in these two cases are 12.2 MPa and 8.3 MPa, respectively. It is obvious that under the combined action of the three types of pre-supports, the stress it bears is less than that of the pipe roof support alone. This is due to the interaction of the three types of pre-supports in Case V. Although the pipe roof can only provide local constraint in a limited area around it, the surface grouting increases the overall stiffness and strength of the surrounding rock. In addition, the anti-slide piles also prevent the landslide from recovering to some extent. Under the combined effect of the three types of pre-supports, the excavation area will be more stable and the support structure will be safer.
+|-style="background:white;"
 ==4.3 Reinforcement effect of pre-supports on tunnel==

@@ Line 176: / Line 176: @@
 ==4. Results==
-==4.1 Reinforcement effect of single pre-support on landslide==
+===4.1 Reinforcement effect of single pre-support on landslide===
-First, the reinforcement effect of a single pre-support is analysed. The deformation of the landslide mass after tunnel excavation under five cases is shown in Fig. 6. Due to extremely unstable geological conditions, significant deformation and displacement occurs during tunnel excavation. At the same time, the tunnel excavation creates a free surface and the soil is subject to its own gravity, moving and deforming downwards. At the foot of the slope, the soil is subject to the greatest force of gravity. Therefore, in all cases, the greatest deformation occurs at the foot of the slope where the tunnel entrance is located, pointing to the lower right, and the downward deformation is slightly greater than the horizontal deformation. As the position moves upwards, the deformation becomes smaller and the direction tends to be more horizontal. The maximum displacement of the slope in the Case I reaches 15.1 cm, indicating that the entire landslide has undergone significant overall sliding and will be in an unsafe state without support. The maximum displacement of each landslide mass in Case II, III, IV and V is 14.3 cm, 9.8 cm, 8.9cm and 8.5cm respectively, which is a decrease of 5.3%, 35.1%, 41.1% and 43.7% compared to the maximum displacement.
+First, the reinforcement effect of a single pre-support is analysed. The deformation of the landslide mass after tunnel excavation under five cases is shown in [[#img-6|Figure 6]]. Due to extremely unstable geological conditions, significant deformation and displacement occurs during tunnel excavation. At the same time, the tunnel excavation creates a free surface and the soil is subject to its own gravity, moving and deforming downwards. At the foot of the slope, the soil is subject to the greatest force of gravity. Therefore, in all cases, the greatest deformation occurs at the foot of the slope where the tunnel entrance is located, pointing to the lower right, and the downward deformation is slightly greater than the horizontal deformation. As the position moves upwards, the deformation becomes smaller and the direction tends to be more horizontal. The maximum displacement of the slope in the Case I reaches 15.1 cm, indicating that the entire landslide has undergone significant overall sliding and will be in an unsafe state without support. The maximum displacement of each landslide mass in Case II, III, IV and V is 14.3 cm, 9.8 cm, 8.9cm and 8.5cm, respectively, which is a decrease of 5.3%, 35.1%, 41.1% and 43.7% compared to the maximum displacement.
-To further compare the effect of each pre-support, the displ acement of key points A1-A9 under different cases is plotted as shown in Figs. 7 and 8. It is shown that after the application of the anti-slide pile, the horizontal and vertical displacements of key points A1-A9 decrease very little to the point of being negligible. The main reason for this is that the key points A1-A9 are located above the tunnel centerline, while the anti-slide pile was placed on one side of the tunnel, so the control of the landslide mass on the tunnel centerline is relatively weak. However, considering that this project is a segmented tunnel, and the subsequent excavation of the right tunnel may affect the left tunnel entrance, the main purpose of placing the anti-slide pile here was to resist the sliding force of the landslide mass by the strength of the anti-slide pile itself, thereby changing the stress state of the rock and improving the stability of the landslide.
+<div id='img-6'></div>
-The horizontal displacement reduction of the three key points A7-A9 is not significantly different due to the surface grouting being applied for a total of 60 m in the direction of the tunnel. Similarly, the vertical displacement reduction of the five key points A5-A9 is not significantly different as the pipe shed was applied for 40 m. It is crucial to establish appropriate dimensions for the pipe shed and surface grouting range when dealing with landslide mass. Analysis of Case I reveals that pre-support is necessary to prevent significant horizontal displacement of key points A7-A9, while the vertical displacement of key points A5-A9 remains within a small range (<10mm). This demonstrates that the original pre-supports design of the reinforcement range for surface grouting and the length of the pipe roofs is reasonably appropriate.
+To further compare the effect of each pre-support, the displ acement of key points A1-A9 under different cases is plotted as shown in [[#img-7|Figures 7]] and [[#img-8|8]]. It is shown that after the application of the anti-slide pile, the horizontal and vertical displacements of key points A1-A9 decrease very little to the point of being negligible. The main reason for this is that the key points A1-A9 are located above the tunnel centerline, while the anti-slide pile was placed on one side of the tunnel, so the control of the landslide mass on the tunnel centerline is relatively weak. However, considering that this project is a segmented tunnel, and the subsequent excavation of the right tunnel may affect the left tunnel entrance, the main purpose of placing the anti-slide pile here was to resist the sliding force of the landslide mass by the strength of the anti-slide pile itself, thereby changing the stress state of the rock and improving the stability of the landslide.
-[[Image:Review_826582983555-image8.png|324px]]
+<div id='img-7'></div>
-[[Image:Review_826582983555-image9.png|372px]]
+<div id='img-8'></div>
-[[Image:Review_826582983555-image10.png|372px]]
+There are significant changes in each key point after construction of the surface grouting and pipe roof. The reduction in horizontal displacement after surface grouting is greater than that after pipe poof installation, and this difference is greatest at point A1. At the three key points A7, A8, and A9, the difference in the reduction of horizontal displacement between the two becomes very small. The reduction in vertical displacement at key points A1-A5 after the construction of the pipe roof is greater than that after surface grouting, and the difference is also the largest at point A1. At key points A6-A9, the reduction in vertical displacement after surface grouting is greater than that after pipe shed construction, but the difference between the two is very small. The varying reinforcement effects demonstrated by these two types of pre-supports are primarily attributed to distinct reinforcement mechanisms. The suppression of landslide deformation by the pipe roof is mainly due to two factors. Firstly, the pipe roof solidifies the surrounding rock mass of the tunnel through grouting, improving the mechanical properties of the surrounding rock mass and exerting a restraining force on the landslide mass, limiting its deformation and displacement. Secondly, the pipe roof itself has great stiffness, and the rigid structure can withstand the lateral pressure of the landslide mass, reducing the deformation and loosening of the landslide mass. Finally, the presence of a pipe roof can alter the contact area and contact mode between the landslide mass and the ground, resulting in a decrease in the frictional force between them. As the suppression effect in the horizontal direction is mainly transmitted through friction, the reduction of friction weakens the suppression effect of the pipe roof on the horizontal direction of the landslide mass. However, pipe roofs can only provide local constraint to the landslide mass and cannot comprehensively suppress the entire landslide. Since landslides are typically large systems, pipe roofs can only provide restraint within a limited range, thus their inhibitory effect on the horizontal direction of the entire landslide is limited. Surface grouting is a process that involves injecting high-strength cement mortar into soil and then chemically or physically reacting with the soil to increase its cohesion and internal friction angle. This improves its shear strength and sliding resistance. Additionally, the grouting mass fills gaps and cracks in the surrounding rocks, forming a dense consolidation body that increases the overall stiffness and strength of the surrounding rocks. Surface grouting controls lateral displacement by passing through vertical steel pipes and the entire landslide mass from the surface.
-'''Fig. 8 Vertical displacements of key points A1-A9 in different cases'''
+The horizontal displacement reduction of the three key points A7-A9 is not significantly different due to the surface grouting being applied for a total of 60 m in the direction of the tunnel. Similarly, the vertical displacement reduction of the five key points A5-A9 is not significantly different as the pipe shed was applied for 40 m. It is crucial to establish appropriate dimensions for the pipe shed and surface grouting range when dealing with landslide mass. Analysis of Case I reveals that pre-support is necessary to prevent significant horizontal displacement of key points A7-A9, while the vertical displacement of key points A5-A9 remains within a small range (<10mm). This demonstrates that the original pre-supports design of the reinforcement range for surface grouting and the length of the pipe roofs is reasonably appropriate.
-−
-<span id='_Hlk163580083'></span>
 ==4.2 Reinforcement effect of multiple pre-supports on landslide==

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−	The simulation considered five different cases. Case I did not include any pre-supports, Case II only utilized anti-slide pile, Case III only employed surface grouting, Case IV solely installed pipe roofs, and Case V applied all three pre-supports. Nine points on the slope surface above the tunnel centerline (A1 to A9 in ~~Fig.~~ 5, with a horizontal spacing of 10 m between adjacent points) were selected as key points. The displacement of each key point was evaluated under different cases to compare the reinforcement effect of different pre-supports on the landslide.	+	The simulation considered five different cases. Case I did not include any pre-supports, Case II only utilized anti-slide pile, Case III only employed surface grouting, Case IV solely installed pipe roofs, and Case V applied all three pre-supports. Nine points on the slope surface above the tunnel centerline (A1 to A9 in [[#img-5\|Figure 5]], with a horizontal spacing of 10 m between adjacent points) were selected as key points. The displacement of each key point was evaluated under different cases to compare the reinforcement effect of different pre-supports on the landslide.

	==4. Results==		==4. Results==

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 {| class="wikitable" style="margin: 1em auto 0.1em auto;border-collapse: collapse;font-size:85%;width:auto;"
 |-style="text-align:center"
-! style="text-align:left;"| Properties !! <math display="inline">\gamma</math> (kg/m<sup>3</sup>) !! <math display="inline">E</math> (GPa) !! <math display="inline">\nu </math> !! <math display="inline">c</math> (MPa) !! <math display="inline"> \phi </math> &#x03c6; (°) !! <math display="inline">\sigma_t</math> (MPa)
+! style="text-align:left;"| Properties !! <math display="inline">\gamma</math> (kg/m<sup>3</sup>) !! <math display="inline">E</math> (GPa) !! <math display="inline">\nu </math> !! <math display="inline">c</math> (MPa) !! <math display="inline"> \phi </math> (°) !! <math display="inline">\sigma_t</math> (MPa)
 |-
 |  style="text-align: left;"|Completely weathered argillaceous limestone